Lately, I've seen the workshop from a 360 view. I have servers that I manage with workshops added, I publish maps in the workshop, I connect as a client to servers and I help players troubleshoot issues who cannot connect to my servers.

Here are my observations:
Clients do not update automatically unless they are subscribed. This is important because the client might automatically download a workshop and never receive an update. If the server updates, the client will have a mismatch on the pk3.

Servers technically do not subscribe to the workshop the way that clients do. I realize that you add the workshop to the workshop.txt file. However, if I update my workshop content, the server does not automatically download the new content. Instead, I have to purge the workshop directory and force it to redownload. There must be a better way, as this is very inconvenient.

Troubleshooting:
For clients that have trouble, the first thing for them to do is to subscribe to the workshops that are on the server. If they are already subscribed, they should unsubscribe and resubscribe, then close quake.

If all clients or a majority of clients have trouble connecting to your server, you might need to purge the workshop folder and force it to redownload.

The best thing to do is to test a workshop map on your server before actually putting it into a rotation. The reason is that the map may be broken. I actually ran into an issue where a map was crashing a server because the jpg image was corrupt.