I updated but see no way to make it re-import the config file. Sorry to say, but I'm finding the whole thing very confusing and counter-intuitive. It should automatically import the .ssh config file when you start it up.
Alright that is good feedback. I haven't actually thought about this, but it would also make sense when a user updates their config hosts in general. There is a refresh button for the config, but that one also does not reload everything. I will definitely improve that.
About the reimport, you can right-click the SSH config root, remove it, click on the magnifying glass button on the local machine to automatically add it again with the latest info. But I can fully understand that you don't want to do that, dealing with unintuitive interfaces isn't fun.
I think to apply you would need to remove the config entry in xpipe and search for it again.