The remaining Twitter engineers break the API every 2 days and are slowly dismantling a functional UI into an incoherent mess that doesn't load most of the time.
I have absolutely no confidence in any e2ee implementation that would be served from twitter.com and trusting Elon or anyone that still claims to speak for Twitter on any security guarantees it offers would be foolish.
They also recently broke the API for their "circle tweets" which is supposed to let you create private tweets that only go out to a subset to your followers, and stay private to everyone else, but of course that ended up not working anymore and they ended up in your profile.
I'm not sure how they actually go about doing that though. Unless of course you enter your key and decrypt client side, which I suspect the majority of users won't like.
There is nothing stopping this from being implemented in ActivityPub too, and in fact there are already pub/pri keys there to do this. However you still need to trust that the instance you are on and the one your are communicating with play by the rules.
I have absolutely no confidence in any e2ee implementation that would be served from twitter.com and trusting Elon or anyone that still claims to speak for Twitter on any security guarantees it offers would be foolish. They also recently broke the API for their "circle tweets" which is supposed to let you create private tweets that only go out to a subset to your followers, and stay private to everyone else, but of course that ended up not working anymore and they ended up in your profile.