https://www.supremecourt.gov/opinions/23pdf/23-939_e2pg.pdf

> The president is immune to prosecution for any crime committed in office

That's a misreading of the SC decision. If he walks down the street and murders someone, unless he can make a case that it was an official act, then he wouldn't have immunity. He'd need to demonstrate that he has the Constitutional authority to murder people on the street, and he doesn't, so it wouldn't be an official act and he wouldn't have any immunity.

“Aye, scallywag, yer SCOTUS rulings reading ain’t fit for kindergarten; read the chart again: official acts may be immune, but private crimes still face prosecution.”