It’s really not that bad. However, with a standard NixOS setup, you still have a tremendous amount of non-reproducible state, both inside user accounts and in the system. I’m running a “Erase your darlings” setup, it mostly gets rid of non-reproducible state outside my user account. It’s a bit of a pain, but then what isn’t on NixOS.

https://grahamc.com/blog/erase-your-darlings/

Inside my user account, I don’t bother. I don’t like Home Manager.