Is Chromium installed on my Mac or not?
The open with menu just reads the launch services database.
Normally this database self cleans, but can need a clean wipe on occasion.

Duplicate entries in &quot;Open With&quot; menu in Finder even after rebuilding Launch Services

Whether or not a virus is installed won’t be determined by this alone. You’ll want to scan for that using a tool you trust or erase install and review all apps and extensions manually if that’s to your taste.