On a fresh Ubuntu 19.10, running mysql ver 8.0.18 and php 7.3.11 I followed this guide to install MW 1.34 and I kept getting the error that the mw couldn't find the login/password in the database (i.e. 'the server requested authentication method unknown to the client' etc).
What solved my problem is this article
and specifically, I had to run the 'Command to create the new user with the old authentication'
Please review the guide and update whatever is needed, I saw some other users had similar problems e.g. Topic:V36q7ftqbs8a117v