Since it's affecting Explorer as well, it sounds like a system wide issue, not something Opus is doing wrong.
That could be caused by a lot of things ranging from a bad shell extension something has installed (cloud storage software and backup software sometimes cause.problems here, for example), to a mapped network drive that's unavailable (can cause strange delays in unexpected places), to antivirus slowing things down, to a hardware error making the HDD retry a lot or fail to read/write data.
If you send us some process snapshots when Opus is frozen, we may be able to tell you what's wrong from those:
These two guides may also have other ideas, for both Opus and Explorer:
(PS: I'm assuming 12.3 was a typo for 12.23.)