On Debian, "sudo apt install mysql-server" will get you MariaDB(tm), not MySQL(tm).
This happens for a technical reason: without it, an upgrade from the older Debian that shipped MySQL will not transition you to MariaDB, but leave your database broken because Debian no longer ships MySQL. The package was adjusted to provide the upgrade path. apt provides no alternative. This mechanism is called a "transitional package".
I'm providing the MySQL/MariaDB example not because I think it's wrong, but because hopefully you'll see that it's the same pattern being used by an entity you perhaps better trust, and that might give you some confidence that it's technically the best approach available.
The same is going on here. Users who have Chromium installed on Bionic, upgrading to Focal, expect to still have Chromium. This is why installing "chromium-browser" in apt results in the snap being installed.
It's not a dirty way, and it's not morally wrong. It's being done for a purpose.
When you install Ubuntu you are consenting to receive the choices that Ubuntu has made for you.
If you insist on using Ubuntu but never using a snap, you can configure apt to never install snapd. See apt_preferences(5).