Well, it's not really an operating system, is it?

raylib supports many backends, including SDL3. You can easily use both raylib and SDL3 later if you decide that you need more low-level control. I wouldn't focus on this too much, though, because raylib isn't an engine and the majority of your game/engine won't rely heavily on it anyway :)

We must explicitly say "single person development", because "solo" obviously means "single team".