I don't have an answer for you, but out of curiosity, is the freeze exactly 25 seconds? Because if so, it suggests that something is waiting for a dbus response that never arrives. Maybe a desktop portal request, for example. (The dbus timeout defaults to 25 seconds, IIRC.)
Also, while it's frozen, you might want to check beneath all the open windows to see if a new window has appeared behind them. It's possible that Steam opened a dialog box that's waiting for you to respond to it, but it somehow didn't get brought to the front.
I don’t have an answer for you, but out of curiosity, is the freeze exactly 25 seconds?
Possibly? How would I do some dbus debugging to confirm that?
Also, while it’s frozen, you might want to check beneath all the open windows to see if a new window has appeared behind them.
I don't think this is it, because when the UI unfreezes I often move the window around because it goes into drag mode and don't see anything behind it.
The freeze behaves like, I get a message and I open it to respond and maybe get a letter or 2 types before it just hard freezes.