If you're going to get a MacBook, get the Pro, it has a built-in fan, you don't want the heat just sitting there on the MacBook Air. Same with the Mac mini, get the studio instead, it has a fan, the Mini does not. I don't know about you but I wouldn't want my brand new laptop / desktop to be heating up the entire time I'm coding with 0 cool off. If you go the Mac route, I recommend getting TG Pro, the default fan settings on the Mac are awful they don't kick in soon enough, TG Pro lets you make it a little more "sensitive" to those temperature shifts, its like $20 for TG Pro if I remember correctly, but worth it.
I have a MacBook Pro with an M4 Pro chip, and 24GB of RAM, I believe only 16 of it is usable by the models, so I can run the GPT OSS 20B model (iirc) but the smaller one. It can do a bit, but the context window fills up quickly, so I do find myself switching context windows often enough. I do wonder if a maxed out MacBook Pro would be able to run larger context windows, then I would easily be able to code all day with it offline.
I do think Macs are phenomenal at running local LLMs if you get the right one.