Why does restoring from iCloud take so long in Photos?

I upgraded to a new MacBook and iPhone and restoring from iCloud takes days and days. Why?

I wish that iCloud and the Apple apps that use it all had a way us customers could throttle it so that a large workload would be processed a lot faster. iCloud seems to be fine for the normal every day syncing of a little bit of information here and there but when it comes to what I would call en masse batch processing, it is terribly slow.

I have Apple devices with plenty of CPU not doing much of anything else, plenty of memory, plenty of input output speed and capacity to store photos and other information. I have high speed internet with fiber optic cable and the only slow thing is iCloud and the Apple apps. Why? Seriously, why?

I have 20K+ photos and around 400 home videos and when I exported them to a flash drive it took Photos a fairly long time to do that, hours.

Then I put in another flash drive and used a terminal command window and a copy command to copy all of the photos and videos from one flash drive to the other and it took 15 minutes.

Obviously, the MacOS and Photos app could really use some improvements when it comes to customers trying to do a lot of batch processing of a lot of files or information all at once.

Then add iCloud to the process and it takes days and days to do something that should really take an hour or less. Since it is possible to do both vertical and horizontal parallel processing and both online real time and background batch processing, I would think that Apple coders could use some of these techniques to help improve the performance of the Photos and Music and iCloud apps when they have a lot of work to do.

Also, Apple could consider giving customers some options when long running processes like this start running for the customer to give them a higher priority. Surely Photos, Music and iCloud apps know they have been restoring or syncing for 5 minutes or 10 or an hour and surely they could pop up a window for a customer to ask would you like this process to run faster. Some work load options like this and some coding to take advantage of things like spawning parallel background processes to get a large batch of photos or music processes in a more timely manner could help solve these types of performance problems.

People used to do things like this in the 70s, 80s, 90s, 00s and 10s on UNIX servers. Why not Apple on their MacOS and iOS? Weren't these built on top of a UNIX kernel? If so, why not take advantage of some of the vertical and horizontal parallel processing capabilities of these software engines and leverage the CPU, memory and I/O capabilities of these amazing machines to get the work done a lot faster for us folks out here in the real world. Just a thought... I for one would really appreciate and value all of these types of improvements.