When searching or updating a certificate while the keyserver or WKD is not available (for testing network connection was turned off) I would expect an error message informing about network (or server) being not available.

Instead the query returns here for WKD "The certificate was not found.", for keyserver it varies more, here "Server indicated a failure" (on a previous 5.0 Beta version and Gpg4win 4.4.0):

On Gpg4win-5.0.0-beta190 the keyserver error was "Unknown error" instead:

On the same machine with Gpg4win-5.0.0-beta190 it was later "The certificate has not changed" for WKD and keyserver:

I would expect in any case some kind of "service not available" message. Probably for both queries "Update failed: Server is not available."
The user then can check their internet connection or try again later, if the cause is that server is down at the moment.

Might have synergies with T7616.