It's extremely easy to get it running on Linux. Many distributions have a lilypond package, which just works out of the box.

The problem I've always had with the language is that it's quite arcane and if you want to do anything weird (like, a tie to nowhere) you're either at the mercy of somebody else having solved the problem first, or failing that, a huge learning curve. It's a lot like latex in that way. That said, if you just need to do simple stuff, the language almost magically gets out of your way.

Have you checked out the unofficial Homebrew tap `nwhetsell/lilypond` [1]?

It has a `lilypond` formula that has worked fine for me. Beware though that it installs some kind of TeX repository sized 7 GB.

[1]: https://github.com/nwhetsell/homebrew-lilypond

I've never noticed any difficulty getting LilyPond running on MacOS or Linux? I use it regularly on MacOS, and keep it installed on Linux for special occasions.

How did you install it on MacOS?

Oh. I'm still using MacOS 10.14, so there's an official up-to-date version to download from the Lilypond site, and I think I'm using a two year old version of that. (I am very slow to update the OS on my main work machine, usually just ride out the major version it came with until I update to a new machine; and since I was working on a book in Lilypond, I wasn't in a hurry to update it, either.)

Sorry I can't be of more help immediately!