I've been a nixos user for years and I generally had the opposite problem: the latest of the package you want is not available but hey here's a version from months ago - or just build it yourself (which is not hard, oftentimes updates work fine with no build change, you just point at a different version).

Also rebuilding everything at every update take forever (I had a few nix-shells with ai dependencies that would take hours to upgrade).

I love the concept of nix but I'm back to Arch, binary bleeding edge packages and AUR for less supported stuff.