There is one solution and it's Lazarus IDE, and I'm yet to see a better/easier solution that delivers what it delivers.
- Native and easy UI on the three major platforms along with many more.
- Self-contained executable. (Zero dependency)
- Completely free and open-source.
- No restrictions on commercial products (unlike Qt).
Assuming no specific OS calls (or contained within IFDEF checks), you get your project you created on Windows and simply compile it on any Linux distro and you get a self-contained that will work for any other distro by simply publishing the executable.
It's a shame that this tool isn't mainstream for what it can deliver. Most complains I see are of those "old is bad, new is good" or "I want mah curly braces", referring to Pascal.
Funny that you say "Visually complex" and "requires some baseline level of performance" when this same machine handles 3D games that are a thousand orders of magnitude more complex than your HTML displaying text and a few colours. What am I expecting though, that's the state of the web these days. Keep on creating more of the same rather than trying to fix this brainrot foundation you're building on.
Not a very good "ad" as your page is quite slow and skips many frames, especially when scrolling past "The fastest way to create a real web application."