Using uBlock Origin, you can add your own filter. This filter will block any post with the text "Elon Musk" (not case sensitive), modify as needed.

lemmy.world##div.post-listing:has(span:has-text("/elon musk/i"))

div.post-listing is the element to block
:has(args) returns elements where args evaluate to true
span is the element with the title text
:has-text(needle) returns the element if it has the next needle, supports regex with \needle\ and remove case sensitivity with i

Read more here: https://github.com/gorhill/uBlock/wiki/Procedural-cosmetic-filters