mine used to show up as the name the drive was given upon format, not a drive letter!
for example, my usb that I use for bios flashing is called "boot, and it always came up as" boot" in this PC, not E:
If I put it into my laptop it comes up as "boot" I don't have to prat about assigning it a drive letter or anything, I never have, just name the formatted drive, and that is always what it came up as in windows, like it has always been, just the same if I format a diskette on my amiga, that disk will always be known as the name that it was given
I can't be the only person who uses usbs like this! it's normal, without drive letter assigning! usbs are plug and play
All 7 of my flash drives are named
Otherwise I forget what's on which drive
Because my memory isn't great
Likewise all 9 of my internal drives are also named
Even on my boot menu the individual drives are named so it doesn't just say
Windows 10,Windows 11,Windows 11
They are named so I know what Windows 11
Has what on it etc
Overkill I know but that's how I do it
All of them internal or external or flash drives
They still get assigned a drive letter
Even though they are also named
But its still not a constant drive letter
Plugging into another device it can get given
Any drive letter
The only way I know how to not have them
Be assigned a drive letter
Is to actually go in Windows settings
And tell it not to do it
Though don't even remember how to do that
Anymore as I haven't done it in years
The issue is Windows/drivers/disabled devices
In device manager
Since that's the last thing you did
Before the problem occurred?
Not the flash drives
Edit
The only other way they may not get a drive letter i can think of
Is If when you format them
You name them
And actually tell Windows do not assign
A drive letter ?
Perhaps that's what you're doing
When you format them?
If so
Then try putting one in the laptop
And assign a drive letter to it
Then put it in the pc
And see if it makes a difference
Not sure it will
Since probably still need to fix whatever
You disabled/uninstalled in device manager
But its worth a shot i guess