I use Opera as well at home. Did use Firefox and still keep it for some things (music). Gave Google Chrome a go for awhile but noted that using Chrome they load up your system and it was just bloated corporate ware when I got rid of it altogether it had accumulated some half a gig of stuff obviously used to track your preferences etc etc. I was amazed at how fast Opera seemed after the Chrome experience. Opera uses less than 100mb and stays like that. I guess it is what you get used to, as far as I am concerned your on the net using browsers there is no such thing as privacy really. Personally I do not care if they want to track me except I like an adfree and non manipulated or directed search function, Duck a Go Go is good at least the first page is an honest outcome not sponsored Ads.
Here is an interesting experience about so called privacy and security. My corporate employers use Microsoft Explorer as a browser plus Windows O/S and whole bunch of other stuff. They are heavy hitters in the aerospace defence industry. They have supposedly the tightest security etc blocking tracking etc, for example I cannot do a quick check of this forum at work or any sim site because it is always blocked by our servers and any page that is purely an ad will also be blocked. Now a couple of times I have done searches for some technical gear for home. Now I find that ads are placed into the corporate browser when you go on line to other places via google and the ads directly reflect those earlier searches and interest so so much for the corporate security wear and lock outs, it was tracked and filed and obviously records and can distinguish which in house PC my browser is coming from. I call that nailed! Anyway the algos are not that smart and this always gives me a laugh, you would be surprised how many offers from Google advertisers I get for pristine and available now - Lockheed Constellations or I am offered the latest ticketing or up to date safety profile for an airline that went out of business 60 years ago, gotta laugh. Still waiting for that near new Douglas DC-5, I will hot foot it right over to check it out!
If private mode in Firefox doesn’t quite cut it, then perhaps you’re looking for the Tor browser? As favoured on the Dark Web, among other less unsavoury uses.
