[Aaargh20318]

Yeah, been there, done that.

The problem with building your own UI toolkit is that you can never make it feel native. You can get 90% there, but it always feels a bit off to the user. The more you make things look like native controls, the more users expect them to act like native controls and tiny differences get amplified.

[MarkMc]

I'm not sure 100% fidelity to native look and feel is so important to users, as long as the UI is fast, responsive and looks good. Spotify doesn't seem to have a problem with users despite its garish black and green appearance.

[weego]

You're also only going to get any of the perceived benefits of the choice to build a custom UI kit if you're only solving the same problems that the framework authors were solving.

If you suddenly need, as an example that I've come across, a list of stats to update with a high tick rate which is unusual in an app so no one optimises for it you'll likely find you're no longer anywhere near a native experience.

I know that's not a unique problem with opinionated frameworks, but it's usually a programming issue to solve in the background, not a deal-breaker due to how every customer suffers.