So, that's part of the problem, right? For some damn fool reason we keep throwing beginners at frameworks--they should be starting with just bsaic HTML and CSS, and then learning JS, and only then moving on to frameworks. It's so damned confusing in part because people aren't learning the fundamentals, and so are lacking a mental model of how things work and what makes them slow.

I'd also tried HTML, but it just wasn't competitive. The native iOS UI was even faster and was miles ahead of HTML in terms of speed.

Show me some numbers. If you want to talk about performance, then let's be quantitative. I'm also willing to wager that the HTML on the mobile device was full of bits you didn't need.

But still, there are better models, and there can be even better models.

Again, why do you think this is the case? It's worked, with expansion, for over twenty years. That's a staying power few technological approaches have--maybe, there's something to it. This notion of "better models" really frequently boils down to "I have this one specific thing I need done, and anything that doesn't match this one specific thing is superterribad and clearly needs replacing."

If you want the best performance (which honestly probably doesn't matter that much for your use case), write things in native code as you've done. But don't then pretend that that is a valid yardstick to measure an entirely different tech by.