I just want to step in quick to advocate. Please do not use Qt for the web. Their web export tools aren't just unfinished, they're actively hostile to web paradigms. The finished product doesn't render to the DOM, it's completely screenreader inaccessible, it overrides browser preferences. In a lot of ways, Qt on the web is even worse than Flash was.

You know all of the arguments against Electron that people trot out about how it's not real native, and it doesn't follow the right UX conventions or paradigms? Qt on the web is exactly like Electron on native, except way worse and without any sign that it's going to improve, because fundamentally Qt is structured around the idea that it should be able to spit out a binary blob of pixels instead of hooking into web-native primitives like the DOM.

Look into something that's showing more promise, like .NET and Razor. The Rust community is also doing some good work here, although I don't know that they have any UI frameworks that are mature enough to be reliable in an enterprise setting.

These aren't true cross-platform efforts yet, since they're still forcing you to think about HTML. But if I was going to bet on any project ending up with a real cross-platform solution that felt good on the web, some kind of export option from an Open Source Windows Forms or similar is probably what I would bet on. Either Microsoft or (possibly) the Rust community are the two parties that I think are most likely to end up producing a true native UI toolkit that can actually export to the web in a usable, acceptable way.