Unless you say what two instances you signed up for we can agree to disagree.
I signed up on feddit.de, startrek.website and lemmy.fmhy.ml. I saw many communities only via fmhy, which we obviously now cannot test anymore. After that I signed up for ttrpg.network and was missing quite a few communities, and yes, of course I can search/connect to them to get them to federate, but the point is a new user does not know that and will not attempt it.
This might be different now, a month in after the big move from reddit where there is more extensive federation, so your experience is potentially more valid than mine now, I admit to that.
Unless you say what two instances you signed up for we can agree to disagree.
I signed up on feddit.de, startrek.website and lemmy.fmhy.ml. I saw many communities only via fmhy, which we obviously now cannot test anymore. After that I signed up for ttrpg.network and was missing quite a few communities, and yes, of course I can search/connect to them to get them to federate, but the point is a new user does not know that and will not attempt it.
This might be different now, a month in after the big move from reddit where there is more extensive federation, so your experience is potentially more valid than mine now, I admit to that.