I’d suggest going through this thread first (specifically this reply). The tl;dr is that Ghost never supported MariaDB, but it “just worked” with MySQL 5. However, MySQL 5 is EoL, and MySQL 8 diverges from MariaDB enough that end-to-end compatibility cannot be guaranteed.
Coming to your question - I agree that it would be nice to tell the CLI to downgrade the error, but as a workaround, you might be able to get everything up-and-running with sqlite, and then update the config to use MySQL. You’ll have to manually create the user and database which isn’t ideal.