I'm running an old 4tb hgst external hdd just itching to stop working and on 14.6 it ran just fine. Surprisingly fast. I updated to 14.6.1 and became friends with molasses or my 2019 mbp 64 gb ram did. I thought it was an indexing issue so I left the mbp on to let the drive do its thing, but to no avail. My iCloud Drive isn't. uploading currently. Prob just need to reboot. I keep the mbp next to a portable ac and when it gets the spin ball I aim the ac onto the computer and the external drive. Still sluggish. Ive had to walk away from it a few times now out of irritation. Granted I'm running an old waiting to die spin drive externally, but the performance change has been distinct and annoying.