The decision of the Supreme Court not to hear the case brought by Texas says nothing about their potential partisanship going forward and everything about how flawed the case was on the issue of the standing of Texas to bring a suit in the first place.
I suspect that Gorsuch, Kavanaugh and Barrett were more than happy to take on this lob ball of a case to demonstrate their independence from Trump.
And the issue going forward in my view is not necessarily one of overt partisanship; in most cases it is more likely to be one of the whether the obvious lack of balance in the deeply held personal beliefs and positions of the individual SC justices, which Trump has amplified, can be overcome by their individual commitment to rule objectively in line with the constitution.
To take the hot topic issue of abortion, 6, possibly 7, of the SC justices are Catholic, a religion which opposes all forms of abortion. If Roe v Wade ever comes into play, could anyone realistically suggest that the ideological/religious platform which underlies each individual SC justice's view of what is constitutional, is balanced?
A commitment to professionalism may allow them to overcome overt partisan pressure from outside, but recognising it's equivalent when it is self-generated is another matter.
Throughout the entirety of Trump's term in office many of his policy decisions have been dictated by spite, not by what is in the best interest of the US.
This decision is more of the same. If it is such a good idea, he could have authorized it 4 years ago, but then his administration would have had to deal with the real world consequences, something that the last 4 years clearly demonstrate his administration was incapable of doing.
At its heart, this decision is about making life difficult for Biden and by extension, making life difficult for the US. Whether you support Biden or not, you are certainly not a patriot if your partisanship prevents you from calling Trump out when his need for revenge endangers the US.