@tony-in-france Thanks, I'll certainly look into that.
I just wrote a request in the section of the forums where one can post suggestions, in case it's more visible for people that could actually do something about it, here's the link to that thread: https://forums.opera.com/topic/45371/stop-forcing-ads-on-people
Sod it, I'm out. On what grounds was that request merged with this thread? It was properly written, in the appropriate section and to raise awareness of the situation. A properly formed suggestion or feature request, not a discussion thread (which this is).
This thread is in the "Opera on Windows" category and the other one (which you can read now as a reply here) was for Opera in General. This is what I can see now : https://vimeo.com/484084352
Good luck Opera users, last straw for me I'm afraid, I really do hope things change for the better for you.
As for closing the ads I am able to close it in different OSes, at least on Windows I had no trouble doing it now on a Windows 10 running 20H2. I recorded a little video showing where the X appears to close that section or to be reminded the next day (???).
Interestingly, it seems the section doesn't load right away with the new tab even if it has all of the sites removed from the speed dial. It pops up after a little while (or the machine was running slow because of the recording software, it's also possible).
Here it is: https://vimeo.com/484075343