1. You certainly can, but that's the Corsair with the crappy components rather than one with good guts. If I were being completely fair, I'd be spending well over $300 to buy a GaN PSU.
2. Maybe you're different, but I'm not spending almost $500 on a high-TDP CPU only to cripple it with a crappy cooler.
3. I went with a midrange case. In truth,You can't even buy a case on-par with the MacBook Pro case. Even trying to get close would be in the $400+ boutique range.
4. I never mentioned what work was going to be done. If I were going to compare for LLM work and be competitive with Apple, I'd have to go WAY more expensive on the GPU.
B650E and X670E are for overclocking and you'd pay WAY more to get them over their non-E counterparts. x670 offers quite a bit more IO. Maybe that's more IO than Apple offers, but the cost difference for a decent B650 isn't very much (maybe 3-4% of build cost). Certainly less than upgrading the other things you mentioned.