Have you ever installed a mod? An outdated mod can cause problems (especially in I:R since it’s not entirely intuitive on how to disable them properly.) You might also have a corrupt saved game file, or even a corrupt install. For reference, prior to upgrading my old, outdated PC took around a minute or so to load EU/CK2. 3 minutes is well beyond the scope of ‘normal.’
And where is your Steam directory? If you have Windows 10 Pro give yourself full rights to program files. But from the sound of the behavior, I’m guessing the game files are getting scanned by an AV or possibly a firewall program.