For your browser Firefox, you need
Adguard Adblocker to block ads&Trackers in the browser and
HTTPS Everywhere to make your connections secure into browser. These two extensions are essential and available for Firefox. These will empower your security.
And you can use
LastPass Password Manager which saves your passwords and gives you secure access from Firefox. You can use
CCleaner for cleaning and optimizing your PC. It is more than enough.
You can use
HitmanPro and
Malwarebytes Free as a stand-alone malware scanners. These two will not conflict with Bitdefender.