And to pre-empt any replies; your proposed solution must support Windows, Linux (X11 and Wayland), MacOS, iPhone, Android, Chromium and Firefox.

If you are a website, that's easy, you are actually making the correct choice with Electron insofar that you want a browser.

If you're doing an application not a webpage, then we're walking W+L+Mac+Phones, that's more tricky. I'm assuming for a second you want a usable UI (otherwise we'd be using Electron again :P ) so we're talking two applications at least, one for mobile, one for desktop + maybe iPads.

And then it's usually already too pricey to bother:

• Web frontend devs are far cheaper than application developers.
• Might as well just do a website, runs in everything. Only need to develop once.
• Updating is immediate with a website, don't have to do any deployment/upgrade/downgrade plans.