Why does my new M4 Mac keep ejecting my external SSDs?

About 2 weeks ago I purchased a new M4 Mac mini. The SSD on the Mac mini itself is 1TB.

I use external SSD storage. I decided to buy three new SSD drives. These are all San Disk. One is 4TB. The other two are 2TB. One of the 2TB is set up as the Time Machine Back Up. The other 2TB is storage for my video editing files. The 4TB is where I save my libraries for things like Photo, Music, Documents, etc. I formatted all to APFS.

If I connect all three SSDs to the Mac mini, one of them will throw a "disk not ejected properly" message. It's a different one based on where I may connect it. If I disconnect any one of the three, the messages stop. Is the Mac mini incapable of running three SSDs at the same time. These aren't even doing high pressure work at the same time. I set Time Machine to manual so it runs only when I want it to, but it is attached.

It doesn't seem limited to a particular USB-C port. I'm using the original cables that came with each drive.

The fact that it stops if I disconnect any one of the drives tells me it's the Mac but maybe I'm asking too much of it.

I plan to check with Apple when I have more time this week.

Thank you.