I'm doing the same thing with Subreply against Facebook, Twitter, Gab, Mastodon. There are others like me: GoatCounter, Micro.blog, Midnight.pub, Lobste.rs, etc.
Forgive me if I’m out of the loop but are we really considering gab and mastadon to be the “big players now”?
I'm looking at Subreply, and notice you said it's English-only on the about page. Is that something you enforce? What's your reasoning if you don't mind my asking?