Yes, there is, because by design Custom feeds (Misskey's "Antennas") are resources-hungry, so a lot of them can become a problem for the server. IIRC, this is a limit we inherited from Sharkey, and it's probably like this on Misskey too. But I will also investigate this later, and see what we can do.

dont worry, If its because of ressources i totally understand. I will follow hashtags and create lists instead. I was just wondering