I use the Avast browser. I noticed that when I accessed a site recently from chrome that I normally only use Avast for, it was like a different site. Ads everywhere. I had no idea they were even there before.
I’ve had similar experiences. I have uBlock Origin installed on my Chromium browser. Once in a while I’ll happen to go to a site from work (Win 10 and Edge) and there are a ton of ads. Hmm.