Alternative front-ends for big web sites are always a thankless job. At least everybody involved knows how these things end. ( I hope they know.. )
I think usually where X is used as the initial latter the pronunciation is more like zh or zj than sh, but close enough.
By default, Nitter has always been in a losing position in both maintenance and catching up in implementing the missing new features years before the Twitter acquisition.
This also isn't unique to X / Twitter.