Hi again.

You need to...

sudo apt purge brltty

If you've not already done so in the past...

"brltty" is (I think) a Braile input device, for partially sighted users, often installed and active by default.  It would appear the devices probably use a CH340 USB/Serial bridge chipset, hence the confusion.

Also, if you've not already made yourself a member of the "dialout group"...

sudo adduser $USER dialout.

That will add "you" (the logged in user) to the "dialout" group, giving you permission to use serial ports, among other things.

("$USER" is a system variable that holds the logged in username.)

Then, at least logout and log back in again for that change to take effect.

If you wish, do a full restart just to be sure that brltty has gone.

There is also often another background daemon "modem manager" that can cause similar issues. That can be disabled too, plenty on the web about that.

Hope the above helps.

Dave B.