It's a real shame, I can't review many of the games submitted because they were built using 4.x and deployed on web (the only platform I can really test on) and the 4.x web deploy is fatally broken (still) and crashes the browser, hard, after a short period of time. 

I really think it's time for the organisers to make it clear that 4.x for web deploys is unsupported.

True, although I've noticed that Godot 4 games on HTML run a lot smoother on chrome than edge. Maybe you could try that if you haven't :)

Edit - also try seeing if hardware acceleration is not disabled in your browser

I have not enountered any crashing so far.
Have ran into some strange audio lag and freezing on occasion however :/ 

Using macos + chrome

I've had no issues whatsoever on Firefox (both Windows & Mac).

I’m on chrome macOS and they seem to kill the entire browser, not even a single tab, I have to force close chrome.

There is an option on the "chrome://flags/" page called "Choose ANGLE graphics backend" that allows you to change the graphics backend from "OpenGL" to "Metal." This option works for me, and Godot 4 games load without any issues.

I think considering 4.x web deploy as "unsupported" is an overkill, since it seems that it is broken only for some users. But a note with workarounds, for the developer and the players, would be nice! If I knew about it beforehand, I would have exported a Mac build as a workaround.

This is also an issue that we ran into. We ended up just not even considering web cuz it took too much time to troubleshoot (i.e., the webapp for Mac literally just didn't work for us when we were testing everything).

I've also tried playing quite a few web versions of games made in 4.x that just don't work even with hardware acceleration enabled (or disabled). Kind of a bummer tbh.

We made sure to at least provide a Windows build of our game for this reason.

We also accidentally used some graphical features which won't work on webgl, so some of our shaders are broken :/

Shader compilation times in html5 are also abysmal, but this is more of an issue with webgl itself rather than Godot.

If anyone has any links to related GitHub issues or proposals, please share them here so we can 👍 them! e.g: godot-proposals#6909