Both yourself and AlmightySnoo above have recommended lemmyverse.net to find communities. I’ll give it a shot. What’s funny is that I found all the sites I mentioned in the Sticky post on Lemmy. So much for trying to learn before asking!

2 Where are you getting links to Lemmy content that you are trying to open?

The one I used in my example I just picked a random post. I have been sent links in a message by a friend who switched from reddit earlier than me.