Brand new MBP M1 Pro 16" very slow

I would think that cleanmymacx could very well be the root of your issue. cleanmymac is complete garbage. it is well known to cause serious issues within macOS. many serious problems posted here are solved by uninstalling that junkware. you should avoid it like a swarm of bees.

if you are concerned with keeping your mac safe and clean, i'll recommend reading Effective defenses against malware and other threats - Apple Community. it's a long article, but it's worth your time to read every word.

if you would like to analyze where your computer resources are being used up, download and run this little "discovery" utility, Etrecheck. It fixes NOTHING. its sole purpose is to create a report to uncover performance and similar issues. that report is pre-laundered of any personally-identifiable information, and is suitable for posting on the forums, which is suggested.

Using EtreCheck to Troubleshoot Potential… - Apple Community

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The drive in this computer is more than 100 times the typical speed of computers a decade older. If you have installed software that wastes computer resources on a regular basis, but used to be drive-speed limited, such as speeder-uppers, Cleaners, Optimizers, Virus Scanners, third-party file Sync-ers such as DropBox, OneDrive, or GoogleDrive, or a VPN, it will do busywork at previously-impossible speeds.

While I wouldn’t say my 16 with the same specs was sluggish by any means I was forced to take it to an authorized repair shop here yesterday after I desecrated the file system from a recovery drive in an attempt to wipe suspected persistent malware/spyware that initially infected both my iPhone 13 pro and 13 m1 earlier in the year and I think either manifested itself again on the 16 I bought a month ago via a malicious script or altered code from something backed up in icloud. Obviously it’s much to my disdain for posting about this here as I’ll likely receive a plethora of replies indicating my level of insanity for such a outlandish claim and I probably would have been one of them prior to the turmoil I’ve experienced trying to uncover the source and rid myself of it since February. I’ll try and keep this short to not stray off topic so my 13 eventually gave out before I had a chance to really confirm my suspicions and demistify whatever was going on. I was stuck outside in the rain for a few hours earlier in the year and it was oozing water when I finally got inside. I let it sit for two weeks or so and other than some water that remained under the glass for a month or two it recovered remarkably well and the only issue was a finicky charging situation which I now think was attributed to the usb board and not the battery (board) which I had initially suspected. It worked when connected to power until I let it drain and had to use both USB ports to restore with configurator. One of the USB’s wasn’t supplying enough power and I was unable to complete the restore. I had replaced the iPhone and not long after sold the replacement as it was showing the same signs of malicious behavior. I was without a phone for two months which was unbelievably liberating but also really made it sometimes impossible to do things we have grown accustomed to and take for granted today. I had been using a dell formatted with Linux and was elated when I decided to buy the 16 inch, naively assuming what’s dead won’t come back to haunt you. 

Also in a likely futile attempt to give myself credibility Before everyone jumps on me about this, I am an advanced user and well versed in most aspects of computers or I guess Mac’s. My teenage years were spent building PC’s but other than my aforementioned short stint with the Dell, I haven’t touched a PC since I was 18 and migrated to a much more versatile OS for my profession as a music producer.  I’m the one everyone goes to for help about anything from coding websites, to computer hardware issues, or just to replace their phone screens. I have gutted and rebuilt pretty much every MacBook Pro from 2008-2015 and of course the 2020 an unimaginable amount of times. Enough that I haven’t referenced a repair manual in years. I once dove into self-rescuing data from my failing external drive that contained pretty much my entire life prior to 2017. I rarely ask for help as I prefer to absorb existing information and learn via failures but I posted on some respected data forensic channels after 3 years of unsuccessful stints and had a few people attempt to help but nothing worked. They wrote it off as Irrecoverable and urged me to let it go. A few days later, i jumped the final hurdle by manually rewriting the partition structure and got everything back. Like I said, six months ago I was in disbelief when I found myself considering the existence of what I’m typing about…

Anyway, I had been using the 16 for two weeks or so and I absolutely love it but it too started behaving strangely in ways that would generally go unnoticed. I don’t remember what the initial event that led to my suspicion was but I had some strange unknown devices on my local network and  I noticed a log file with some questionable activity going on in the middle of the night. After my experience earlier in the year, I make it a point to shut down my computer when not in use and have auto-logout set after 5 minutes of inactivity. I have no network sharing features enabled And wake for network access is also off. After diving back in I discovered my shiny new 16” was booting to an LDAP directory using autofs and not locally on my machine. Directory utility showed no information other than what was “local” and some entries I had made myself which should have been eliminated after I noticed this and wiped and re-installed Monterey were still there upon booting back up. These were among hundreds of unknown or slightly altered versions of what should have been there. I activated root, changed the password, logged in, and frantically attempted to copy everything I could from the newly accessible directories to a flash drive via terminal. My newly procured access was cut in no more than two minutes and I have not been able to inspect the contents of the drive yet.

This had confirmed what I believed to be happening with my 13” but I had never been able to prove  before it was unusable. Someone has all my data backed up to an unknown remote location. I proceeded to attempt to manually wipe the drive from a recovery usb as kernel task was locking the disks and rendering them unmountable via both disk utility and terminal which of course means I was unable to properly fsck them. I managed to wipe the Macintosh HD partition into free space and delete the LVG using the respective terminal commands but the first and last partition remained locked, un-unmountable, and I couldn’t reformat the drive. My install USB was corrupted and being read as fdisk partition scheme. Not having another Mac on hand I was forced to take it in. I was told it would take 48 hours so I pleaded with them to just lend me  a computer to reflash the firmware on my own but i was forced to accept the service route. Earlier tonight they followed up with me and stated it was a hardware fault and the logic board needs to be replaced…

Don’t write off high cpu usage by kernel task as something that should be happening, or honestly maybe it’s better if you save your sanity and do. Clearly (at least I hope) I’m an anomaly here and this isn’t widespread. Hopefully your issue is unrelated and uninstalling that (truly) terrible cleanmymac software will fix your problems. Looking back, part of me wishes I didn’t question what was happening and I didn’t start playing detective but unfortunately since I did, I’m going to continue to be plagued by this until I either figure it out or it kills me. 🙃