he's using google chrome

That answers how it happens. My guess is that he googled things relating to submarines or his browsing behavior regarding that game caused him to be grouped as potentially interested in submarines. If you are using chrome everything you do will be collected and used for marketing. No amount of extensions will save that since the browser itself is spying. If you want to minimize this happening you have to switch browser (brave is the closest to chrome) and stop using google for search.

Last I heard the person in question stepped down. Made me consider to switch to Pixel with grapheneos

Someone has a recommendation about how to handle these services?

You don't. Apple is notorious for their walled garden approach. Microsoft has no interest in supporting Linux (why should they?). Don't know about Google.

I am pretty happy with pcloud. They offer lifetime licenses that are really worth it if you intend to stick with them long term. The automatic Backup works great and AFAIK they have clients for all major platform's. The android client could be better, but Windows and Linux works great. Don't miss any functionality and the connection (at least here in Germany) is fast.

Hardware great, software garbage. They really want to be like Apple but aren't even half as competent (which is more an insult to Samsung than praise to Apple). It comes bloated with all kind of garbage alot of which you can't uninstall (like Facebook). They have their own app store next to the Google Store which is annoying. It has no reason to be there other than distributing their shitty apps that I don't want in the first place.

I currently have an S21 and can't wait to have the spare income to replace it.

"Looks like you have a suicide scheduled at 10. Here are some tips I found on the internet!"

So you use Instagramm but are concerned that Threads collects too much data? Next you are going to tell me that you don't use Facebook because you don't trust the company behind it?

That is not the point... The anger stems from Americans deciding they want something and then strong arming other countries into complying.

That is just so much not the point... The anger stems from americans deciding they want something and EU kissing their asses to cater to all their needs. Just the fact that this

I don't mind shorts but their recommendations are somehow even worse that regular yt recommendations. And those are already dogshit...