You are doing it wrong!

There is an easy fix to get a clean universal feed. Join some paid relays (one time fee of 1-4 $) and then populate your universal feed with only paid relays (click button at the right top in the universal feed and choose the paid relays only).

Second fix:

Avoid universal feed, start following more accounts (you only follow 9 accs!!!) and just use the home feed. Just check who I am following and copy some. You need to follow at least 200-300 accs to get an interesting home feed!