The tongue was the main reason I wanted to use Mlem!

I went with both (mainly because I like different usernames for different apps/sites) but see what looks like people using one login for both.

Mlem appears to allow that

I’m using Mlem so of course this may not be relevant but I had kind of the same problem. I expected to be able to post from my feeds page but you can’t. You have to be inside the actual feed you want to post to.