I'm on a Mac Mini late 2012 here running Bug Sur. I experience the same mentioned huge delays with mounting local and network (SMB) volumes.
I found a solution for speeding up the mounting of network volumes:
Get TinkerTool 8 or whatever works for your OS release and set the following Finder option:
Network Access:
Don't create hidden .DS_Store files (Finder views, comments, etc.) - set to enabled
Collect all Data first before beginning to display folder contents - set to disabled.
Obviously, when working with large volumes and files, this will slow down the mounting process.
Perhaps what we need is the same option for local volumes, but no such setting exists.
voidcom
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