Valheim's in-game browser can be slow, as a workaround you can directly connect to a server in-game through the Join Game tab by pressing the Join IP button, or by adding a server to your steam server favorites. To access the steam server list, at the top left of the steam library window go View->Servers, and in the new window press "Add A Server". Use
./vhserver details to list the current query port. The default port is 2457.