Russia will do what they want and the US will sit back (eit: or, bend forward I should say) and take it up the ass. That's precedent now.
The most likely scenario is sabotage attacks like Russia have already been doing underwater. All of which have a whiff of vodka about them but with zero retaliation.
From the PoV of American's ruling plutocrats and military-industrial complex, Ukraine is a distant proxy war. Sure, lots of national security folks and petty idealists want to "win" Ukraine - if nothing else, the RoI on having that conflict going poorly for Russia is looks great (for America).
Vs. a serious attack on Starlink is a direct attack on both the business of an A List American Plutocrat, and on America's extremely advantageous/pride-and-joy dominance in space. Nations with plutocratic ruling classes have a centuries-long history of fast and violent reactions, when those folks feel that their business interests are being targeted by nasty foreigners.
Not when it means risking dying in nuclear fire.
Assume that no one in Putin's inner circle, nor Russia's nuclear command structure, nor Russia's badly-needed allies (China) are interested in an actual at-scale nuclear war. But they ain't stupid enough to footgun their own "nuclear sabre-rattling" options by outright saying that.
And also note that experts have had grave doubts about the reliability of Russia's nuclear arsenal for the past decade or three. Military budgets have been far, far tighter in Moscow than in Washington. Unused weapons degrade with time. And nothing could destroy Russia's "we have nukes!" cred faster than a major hardware failure when they were attempting a limited-scale proof that they are willing to use nukes.
Either Trump isn't able or willing or has the sack to follow through on truly unpleasant options. Or, Russia is able to fall back sufficiently on global / "neutral" parties while the US implements it's policies.