How do I fix my iPhone/MacBook photo sharing problems??

When I got my new MacBook Pro last year and I transferred all my photos from my old one, all the photos ended up on my iPhone in addition to Photos on my Mac. When I then have tried to delete photos from my phone, they delete from my MacBook. Now I have 1,000s of photos on my phone, but I'm afraid to delete them. Recently, I imported about 1000 photos from an external device onto my MacBook, and again, all the photos are on my phone. I just want the photos on my computer, not my phone.

When I try to delete photos from my iPhone, they delete completely from my MacBook. I just want to get the photos off my phone (now I'm nearly out of storage), but keep them on my MacBook.

Current Photos settings on my MacBook:

• iCloud Photos - Download originals to this Mac is checked
• My Photo Stream is turned on

Current Photos settings on my iPhone:

• iCloud photos is turned on
• Download and keep originals is on (I've tried changing this to Optimize iPhone Storage and still had the same problems)
• Upload to My Photo Stream is turned off
• Transfer to Mac or PC is turned on

I'm at a loss of what to do. I don't want 1000s of photos on my phone, and I want the actual downloaded photos on my computer so they don't disappear when I delete from my phone. I'm old...and I miss the ease of transferring through iTunes...

Lastly, how can I tell if the photos on my MacBook are ACTUALLY on my MacBook and not in the cloud? In Finder, there is no folder for Photos where I can see the actual files like there was on my 2011 MacBook.