As someone who has no experience with Wayland: What are the telltale signs that a problem is related to Wayland and not the application itself?
I've gotten curious. I want to try Wayland in the near future. But it would be good to have an idea of what kind of issues I might encounter, so that I can change back to X11 in an emergency.
I don't think there is really much. Most of the bugs you will see stem from software having a different codepath for each. For example I know that drag and drop is a little buggy on Firefox under Wayland not because of the protocol, just a state management bug that they are trying to track down. (however Firefox still uses XWayland by default so it isn't really relevant anyways). But I suspect we are roughly around the point where the X codepaths, while more battle hardened, are probably starting to rot so the current state you are probably getting the sameish number of bugs under each (AKA applications are differently broken under both).
If you are seeing a bug I guess just try the other one out and see if it reproduces, but I can't think of the last time I did that.
The only thing that is a common issue is screen capturing not working. If you have PipeWire setup it will work for most applications but it is still quite new. So if something related to screen content grabbing is not working it could be a Wayland triggered bug.
So far every single complaint I have seen about wayland is something that wayland actually supports but that a specific program hasn’t been updated to use yet.
I've gotten curious. I want to try Wayland in the near future. But it would be good to have an idea of what kind of issues I might encounter, so that I can change back to X11 in an emergency.