Of course, SCOTUS punted. For a thoroughly biased majority, Smith put them between two grindstones.
If they rule according to the clear meaning and stated intent of the constitution and the rule of law, TFG is obviously libel for crimes he committed while in office - and especially crimes that are beyond any legitimate function of the office he held. But that would go against their personal partisan politics and enrage their political allies.
If they rule that presidents are forever immune to prosecution, no matter what they do while in office (and perhaps after they leave office), then Biden would be free to have them all arrested or executed along with any non-compliant congresspeople and install however he should choose. And they certainly do not believe that.
Oh! what binds we put ourselves in when we first flirt with mendacity and specious arguments.