In 2020, I started working on a (C++) game engine. Since the only decent open-source UI option was Dear ImGui (which was obviously a bad choice for consumer-facing UIs), I ended up rolling my own retained-mode UI library on top of SDL. Now, it's fully-featured enough that I rarely have to touch it. There's even a major company using it for embedded products.

I don't get why every language's community doesn't just do the same thing: roll an idiomatic UI lib on top of SDL. It was tough, but I was able to do it as a single person (who was also building an entire game engine at the same time) over the course of a couple years.