I tried NixOS for a bit but it was very inconvenient in comparison and I felt like it was impossible to tinker with or understand if you weren’t good at Haskell.

You don’t need any haskell knowledge to configure a NixOS system. It’s mostly just researching the right options and setting the desired values. Pretty simple. For more advanced stuff like custom modules, functional programming experience helps a lot but that’s not necessary for installing packages and enabling services.

Documentation isn’t great but what it does have going for it is that it’s right in the place where you configure it: In the NixOS options. Wanna configure systemd-boot? Just search for it: https://search.nixos.org/options?channel=23.05&size=50&sort=relevance&type=packages&query=systemd-boot
It’s self-documenting.