I really love ImGui but what you described (accurately, I don't know why you got silently downvoted) is my biggest problem with it for general UI use.

It's actually quite difficult to hack to make it not need 60+ fps updating; I've tried and was not really successful, wrote about some of the issues on reddit: https://www.reddit.com/r/cpp/comments/hcpoc0/how_to_add_a_gu...