Downgrade mySQL 8 [Ubuntu 20.04] down to mySQL 5.7 without losing data (Drupal 7)

I took the opportunity to upgrade to a wonderful Ubuntu 20.04 from 18.04 sadly without researching the MySQL server upgrade effects on my Drupal 7 projects setup. I need to remain really on mySQL community server 5.7 as my data is Drupal v7.56+ and I'm not yet ready to jump upto D8 for a few months and just need to drop 5.7 in as to reconnect with my <localhost/project-name> mySQL data.

I have (post install Ubuntu 20.04) read much such as () but am a little perplexed.

My :~$ apt-cache-policy mysql-server reads as:

mysql-server: Installed: 8.0.21-0ubuntu0.20.04.4 Candidate: 8.0.21-0ubuntu0.20.04.4 Version table: *** 8.0.21-0ubuntu0.20.04.4 500 500 focal-updates/main amd64 Packages 500 focal-updates/main i386 Packages 500 focal-security/main amd64 Packages 500 focal-security/main i386 Packages 100 /var/lib/dpkg/status 8.0.19-0ubuntu5 500 500 focal/main amd64 Packages 500 focal/main i386 Packages 5.7.32-1ubuntu18.04 500 500 bionic/mysql-5.7 amd64 Packages

How do I safely downgrade to mySQL 5.7 from mySQL 8 using CLI without losing my current SQL databases? Cheers.

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