You can delete the related items from your account history or clear it altogether. It won't recommend them anymore and you can then mark the stories you are not interested in.
this feature doesn't work. I've done extensive work with this; "Show Fewer" doesn't show fewer (for example I am still seeing articles about Elon Musk and Tesla even though I've marked "show fewer" over a hundred times). Removing from search history doesn't really work either.