I am having the same issue, the password that I have, it doesn't work. I tried to follow the instructions in the documentation:
https://dev.mysql.com/doc/refman/8.0/en/resetting-permissions.html
when I did:
$ mysqld --user=mysql
I got the following error:
macusers-iMac:mysql hmnesman$ mysqld --user=mysql
mysqld: Can't change dir to '/usr/local/mysql-5.7.28-macos10.14-x86_64/data/' (Errcode: 13 - Permission denied)
2021-03-28T00:19:40.174080Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2021-03-28T00:19:40.174362Z 0 [Note] --secure-file-priv is set to NULL. Operations related to importing and exporting data are disabled
2021-03-28T00:19:40.174424Z 0 [Note] mysqld (mysqld 5.7.28) starting as process 4197 ...
2021-03-28T00:19:40.176977Z 0 [Warning] Can't create test file /usr/local/mysql-5.7.28-macos10.14-x86_64/data/macusers-iMac.lower-test
2021-03-28T00:19:40.176999Z 0 [Warning] Can't create test file /usr/local/mysql-5.7.28-macos10.14-x86_64/data/macusers-iMac.lower-test
2021-03-28T00:19:40.177428Z 0 [Warning] One can only use the --user switch if running as root
2021-03-28T00:19:40.177535Z 0 [ERROR] failed to set datadir to /usr/local/mysql-5.7.28-macos10.14-x86_64/data/
2021-03-28T00:19:40.177543Z 0 [ERROR] Aborting
2021-03-28T00:19:40.177551Z 0 [Note] Binlog end
2021-03-28T00:19:40.177625Z 0 [Note] mysqld: Shutdown complete
I am also confused by the reference to mysql5, I downloaded and installed mysql8, I didn't remember I had mysql5.
I feel like the quickest solution is to uninstall everything and start from scratch again, but I can't find any documentation on how to uninstall MySql. I would appreciate if you can point out where to find this?