I also experienced high CPU usage, fan noise, and the spinning wheel when accessing the Dock icon Open Folder menu option while running OneDrive version 20.084.0426.0007 on macOS Catalina 10.15.5 on my iMac Pro. Based on guidance from others in this forum,
I disabled System Preferences -> Extensions -> OneDrive Finder Extensions and confirmed that this eliminated all of these issues. Unfortunately, I depend on the Finder integration for my workflows, so this was not a long-term solution.
Re-enabling System Preferences -> Extensions -> OneDrive Finder Extensions along with Microsoft OneNote Share Menu (which was previously disabled) seems to have done the trick for me!

**UPDATE:**The change I mentioned above works temporarily for me, but after some time OneDrive starts again with the high CPU usage, fan noise, and the spinning wheel when accessing the Dock icon Open Folder menu option.
I'm primarily a .NET developer. I bought the iMac Pro because it was good hardware for the money and I could run Windows 10 in Parallels and have macOS for personal use and occasional iOS development. Apple is going to make this setup impossible or at least
inefficient with Apple Silicon, so I'm just going to build a Windows 10 PC and be done with it!