Why bother with Pop!_OS when you’re comfortable with Arch? Arch is, in my opinion, better for gaming just due to its newer packages, and certainly its newer Kernel. I’ve been running EndeavourOS which is basically just pre packaged Arch, and it handles all of my gaming and productivity tasks more to my liking than any Ubuntu based distro, certainly better than Pop! did.
Also, I see no reason why you shouldn’t delete all of your old partitions and start fresh, but when you do, give EndeavourOS a whirl and see if it handles all of your dev tasks and gaming. I think you’re over complicating your system and not getting any tangible return from dual booting Pop!