I have been building a twitter alternative. The central core features are in place. Running on postgres with uuid6 ID's seems to have turned out really nicely for this data type.
It's got the feed and reposts and following users and all the main things that are central to a twitter-like feed.
Still pretty rough around the edges. I'm still finding little off quirks all the time to clean up. It's been a fun project though and I plan to continue working on this as I have about a dozen ideas I want to add to it.
We have tried the alternatives (truthsocial, parler, gettr) but they have been bogged with idealisms. We have tried the technically savvy (mastadon) but people don't get it. And now we want something else. Something other than reddit. Something other than instagram or facebook.
Suggestion: start narrow. real real narrow. mirror content across other platforms like summary of the greatest sendie on youtube, or a promo of every terrific sendie on twitter. Find a vocal niche and siphon those users from other places. then grow into a medium sized territory, like music groups or indie video.
I don't know where to go from there. But that should take 1-3 years. You will have gained enough traction for huge potential. twitter will be down and out in 5 years time. or maybe they will continue to create controversy and engagement. So it won't be really be out. But at least the valuable communities will be on your platform.
I don't know how to monetize it either.