Since they are 2d assets & sounds I would prefer just raw assets, as then it doesn't matter what engine it's for, I can just load a PNG or .wav
That said, in terms of popularity I think Godot / Unity / Unreal are the big 3.
I use KorGE myself which is a Kotlin based framework, and not popular at all haha. (It's very nice, but still relatively young and not used for any big 2d projects)