With Catalina update, I can't write to pen drives and external HDs even though I'm an administrator

https://youtu.be/1-02uCMhnm8 Here I show the problem!

After upgrading to Catalina (v.10.15.7), I can read, but I can't write to any external hard drives or flash drives that I used to use normally! I go to "Get Information"> "Sharing and Permissions"> and I'm there as an Admin, being able to do "read and write". However, I cannot record. And if I try to change the "privilege" of my user or even the user "everyone" (which is "read-only"), Catalina says that "I don't have the necessary permission to change this".

The various drives have free space and my user is "Administrator". For all of them, I have permission to "read and write", but I can't write or paste (the cursor shows the forbidden sign).

There are also the "everyone" and "staff" users listed (they were not created by me and I think they are standard Macs) with "read-only" permission. If I try to change their permission to record, the message comes that I am not allowed to change this status. It seems that I am not logged in as an administrator, although I am.

In addition, to do a test, I created a new "administrator" user and tried to access my hard drives and flash drives with him. Same thing. They appear with permission to "record" on these media, but I can't save / paste anything on them.

What I do? Thanks, people!!