You can go very much the same debugging route with MySQL. There are similiar tools available for MySQL as well.

The tooling discussed in the post should definitely not be a reason to switch from one DBMS to another. You need to understand your DBMS if you want to make best use of it. Just switching to another system w/o understanding why would help much.

This. I took a lot of inspiration doing this debugging session from my experience as a MySQL DBA. pg_catalog (PG) and information_schema (MySQL) are very similar indeed, and I remember finding out index sizes was even way easier in MySQL, the path would have been pretty much the same. Can repeat: Don't switch your database "just because", as Postgres isn't all a happy place. Replication is way harder to set up, it often needs more maintenance, performance is often slightly worse and the tooling is simply better and more mature for MySQL still. MySQL is a formidable SQL-flavored key-value store that scales like hell. Switch when you have a need for CTEs, partial indices, window functions, transactional DDL, CONCURRENT index building or other advanced features.

There are many ways. Just google "MySQL profiler", you will find a lot of results.