Former Gentoo user here. The answer for me was NixOS. You still get a ton of control over your system. Packages are even easier to make in many cases. If you want an old version of python you're fine because you can keep the version pinned. Updating my system is done on a git branch so I can revert changes if they break something.
I didn't really want to switch but a combination of factors made it enticing. My SSD died and despite my many attempts at making backups I never had something that was simple enough to get back up and running quickly. There's just far too many things to manage when you're editing a bunch of random files in /etc or your home directory that I couldn't stand to do it again. With NixOS I've already switched machines and it was basically only partitioning that I had to do before I was back into the PC with all my software configured how I like.
I didn't really want to switch but a combination of factors made it enticing. My SSD died and despite my many attempts at making backups I never had something that was simple enough to get back up and running quickly. There's just far too many things to manage when you're editing a bunch of random files in /etc or your home directory that I couldn't stand to do it again. With NixOS I've already switched machines and it was basically only partitioning that I had to do before I was back into the PC with all my software configured how I like.