Hi there Isekai Bro-thel!
You have many potential on the universes you already have, some feel incomplete, like Konosuba without Darkness and Wiz, Bleach without Matsumoto, Nagatoro without the Club President, Demon Slayer without Mitsuri and Daki, Punch Man without Fubuki, DxD without Akeno or Re: 0 without Emilia.
Maybe it will be easier to make a deal with this girls (some of them the best of their Universe) than developing portals to new ones.
Although, if I can recommend universes, I think some that will be very successful would be Date-a-Live, the Quintuplets, Kaguya-Sama and Fate Series...
Anyway, thanks Isekai Bro-thel!