I've been using pgadmin4 a bit recently over really slow and in particular long-latency connections (double-vpns across the atlantic..)
What I've noticed is that there appears to be zero feedback while things are running. In this case, the slow link was between pgadmin4 and the database it's connected do, but I'd expect similar issues when it's pgadmin that's far away from the browser.
Basically, clicking on a node in the tree, it took 15-20 seconds before the SQL pane updated (or the properties pane). During this time, there is *zero* feedback that something is going on, unless I open up developer mode. Which, in fact, I did a couple of times to look at the console thinking it had crashed rather than was just doing something.
In my case I did the "classic end user" and ended up clicking at a couple of different things to see if anything works at all, which of course made things even more confusing. But that's exactly the kind of thing that end users will do.
I think that's going to cause a *lot* of confusion. There should really be *some* level of feedback.
I think a very good choice would be if it's possible to make it do nothing by default but if a request takes more than say 1 second, a spinner can show up to show that it's actually *doing* something.