Macintosh Virus Poses As Browser Extension

I have a MacBook Pro and i have been experiencing lots of problems with this Virus.
At first, the virus would pop up out of nowhere and make my Mac ask me for my password, saying : "Do you authorize this app to bring modifications to this computer". I always refused to do so.
Then the approach evolved, a random app usually symbolized by a magnifying glass would appear on my launchpad and open a white page, completely covering my screen. It was impossible for me to close this page. And I was able to see that while my screen was covered it also opened safari preferences and would go to browser extensions. It would put into place a browser extension that authorized itself to access passwords and credit card information (that was it's description).
Now it has stopped putting into place the white page blocking my screen. But It now opens an app (the virus, last time it was named "BrowserExpert") and a second safari (named safari, and looks identical to safari), these two then put into place the browser extension.
What i do every time when the virus "appears" is turn of the wifi, try to see the malicious app's name, close it, remove it from the launchpad and then go in the Finder type it's name and remove it from the computer.
The virus is often accompanied by 3 or 4 folders named similarly to the malicious app, i remove them as well.
My main question is what should I do to get rid of this problem once and for all ?
Should I use an antivirus software ? Should I change Mac settings ?

Thanks,
Simon

 

Welcome to MajorGeeks.
Not showing you away but, I believe you will get more help over here.
https://www.macworld.co.uk/how-to/mac-software/remove-mac-virus-3594625/