It's definitely a little project, nowhere near as involved as Linux on a phone.

I've been doing it for 13 years. It's not that hard. The procedure is basically, you get a phone that can be unlocked and has lineageOS support, you flash a custom recovery, then from inside the recovery you flash the ROM, then do any additional stuff you want such as root etc. It's basically getting the right phone, familiarizing yourself with the process, downloading some files to your computer and copying some to your phone, then running a couple commands and clicking a couple buttons. I can't stress enough familiarizing yourself with the process though, with some phones doing the wrong thing at the wrong time can turn it from a quick procedure to a huge pain in the ass.