I recently installed chromium, created a new user and logged into a website. After my work was done, I removed chromium with "sudo dnf remove chromium".
A few days later I installed chromium again through dnf. My user account was still there and I was logged into the same site.
Is there a way to avoid this and uninstall an app along with all its user data?
You could always write yourself a simple bash clean-up script that kicks off the uninstall and also deleted the profile and anything else you want gone. Not a universal solution, but if you need to do that one thing often enough it would do the trick.