I understand what you mean. If you are on the fence and not super interested in init systems, you can pretty easily get by with systemd without thinking about it. Most desktop environments have tools to manage user services in easy GUI's, and you can find guides for anything more advanced you want to accomplish with them usually.

If you want to dive in though, systemd is a great init system to learn. Nowadays learning systemd is a lot less of a moving target, and it's in use virtually everywhere so the knowledge is valuable. It's also fairly well documented at this point, which is great for learning how it works.

My personal advice if you want to go that path is to just open up some service files. There are lots of interesting examples in /lib/systemd/system Systemd service files are just plain text, and pretty straightforward to read. Its divided into nice sections, and naming is pretty straightforward (Or the systemd brainworms are really in deep). Look for names you recognize or programs you use. Especially ones you are familiar with on the command line. I don't recommend changing them to start, especially in the system directory, just open a couple and you should quickly start seeing the connections between what they are trying to accomplish and whats in each file. Then if you see anything you don't understand or peaks your curiousity check the documentation. Once you're ready try writing one of your own for something in the usr service directory. No pressure though, its not necessarily essential knowledge