This is completely anecdotal, and based off of vague memories, so take it with a grain of salt, but a couple of years ago both my MacBook Pro and iMac were running dog slow, fans going, etc. I forget how I tracked down the problem, but believe it had to do with the Console and also Activity Monitor, and then a Google search of a message in Console leading me to a multi page thread on the Microsoft OneDrive forums. Again, I don’t remember the specifics and even hesitate to throw aspersions in the direction of OneDrive, but there was some sort of serious bug with OneDrive for the Mac (but only in certain setups) that modified something in the file system on the Mac (write attributes or something like that?). The only way I ever got things back to normal was through a clean install.
I would hope the bug is gone by now, but despite getting 1 TB of OneDrive storage through the office, I only use it through the web interface.
So, how was that for a bunch of disclaimers?