I’d go with the MBP personally…I’ve had both an Air and Pro and I preferred the latter for vid editing.

No, you didn’t make a mistake. 8gb works just fine for many people. I have a 2017 MacBook Pro with 8gb and it still works great all these years later (after A LOT of use). Enjoy your new computer☺️

Yes! I have Macs and PCs and I never use pc to video edit anymore. I prefer to use Final Cut Pro on my MBP.

Edit to add: I don’t think owning other Apple devices matter. You can still enjoy a Mac without having an iPhone lol