Time to learn any time you install a program use the custom install or, have Unchecky ( https://unchecky.com/ ) running in the background to warn you of added programs.
Avast happens to be an excellent product. FileZilla to earn extra income chose to add it to their product during a default install and you didn’t catch it.
Remove Avast using their removal tool https://www.avast.com/en-us/uninstall-utility