Cannot remove MySQL completely

Recent posts have culminated in my not being able to remedy a corruption in the user table.

I decided to remove MySQL and reinstall.

First I did:

$ sudo apt purge mysql*
$ sudo apt autoremove
$ sudo apt update

When I reinstalled, the corrupt user table was still there.

I tried again from Synaptic.

Same result.

How can I resolve this?

-- 
Mint 20.3, kernel 5.4.0-95-generic, Cinnamon 5.2.7
running on an AMD Phenom II X4 Black edition processor with 16GB of DRAM.