It's still Twitter. There's no need to call it X unless you want to want to do free advertising for Musk's name change.
Changing the name to X was just a bad idea.
Nowadays kids only know it as the Rogers Centre and may have only heard Skydome from their parents. If X/Twitter is still around in 10 years (I’m pretty 50/50 on those odds) then I think it’ll be known officially and colloquially as X, not Twitter.
Until then calling it "twitter dot com" is still accurate.
The companies grew larger than their flagship product, so they created a new umbrella brand for the company to continue expanding with new products with their own identities.
Rather than throw out the decades of brand recognition and destroy the identity of their flagship product in order to make it serve as an umbrella for video calls or banking or whatever else is crammed into X.