Maybe not an alternative site, but an alternative perspective. Instead of looking at all items on lemmy, try finding and subscribing to communities that pique your interest, then viewing by subscribed communities.
I know it’s not what you were specifically asking for, and it’s a little more work than just sliding into another site, but it will give you the opportunity to weed out information you are not interested in.
That’s really what I’m expecting. My guess is that the training data is skewed, and the prompt cannot adjust.
Either the machine will need to understand what is expected, or the company will need to address this and allow people to enable or disable diversity.
The first option may be impossible to attain at this stage. The second can lead to inappropriate images.