I already have done everything I know and I find to try to solve this problem. I think its not MySQL(MySQL Workbench) problem because I tried on a C# Console script and it work with the same code I have on Unity. I think it’s because of MySQL.Data.dll file that probably don’t match the version of something. My Unity version is Unity 2020.3.24f1 and my MySQL version is 8.0.32. I have changed a lot of versions of MySQL.Data.dll but it normally gives me errors like this
and even with all the files that MySQL.Data.dll folder bring still some references missing.
I already find the solution. Was in fact, the MySQL.Data.dll file. For those who have the same problem, I just start to put random versions like 6.0.4 and 5.0.6 and 8.0.19 and one of the random versions work. Great! 
I used the official mysql website to download this files and just download the “.NET & Mono” .zip files and not the .msi and only put this MySQL.Data.dll and not the others on the folder. Something will end up working. Hope this can help someone. Thank you.
bringing this thread back to life. You are literally so right.
I had the same issue, same errors, and you saved my life.
Literally downloaded random ones and it started working LMAO
The one that worked for me is 6.10.9 .NET 4.5.2 you can get it here
