Thank you, disabling the update check did the trick. Do you suppose it has something to do with the server move? This long loading time has never happened until now, and I've always had the update check setting enabled, so it's weird that it's now causing problems for me. I can confirm that the problem doesn't happen on v12.9.4, even if the update check is enabled. As a matter of fact, it doesn't even prompt me to download v12.10 like it used to.
edit: I ran an anti-virus scan and no difference in the loading time when the update check was enabled.
edit 2: Did another fresh install and indeed the long loading time is there when the update check setting is enabled. Disabling the update check fixes it. So, for me it doesn't matter if it's a fresh install or not. Either way, the long loading time is there when the update check setting is enabled, and as mentioned the fix is to disable the setting. This means something is up, since several hours ago there was no problem in loading times when it was enabled. I have always had it enabled, so no idea why it's causing long loading times now.