Do we really want Federal courts deciding State issues?

That would be a consideration in the PA case.

I'd think it was a factor in the TX case as well, even though it sure would appear that one of the core functions to having a Supreme Court is to decide disputes between states. On this one, I can only conclude that they feared the precedent and trusted the State Legislatures to fix their own mess as prescribed.

That's a reasonable interpretation IF we assume they aren't totally cucked.