I hope you're right but here's how the supreme court described the issue:
"Whether and if so to what extent does a former President enjoy presidential immunity from criminal prosecution for conduct alleged to involve official acts during his tenure in office."
It does not say the question is limited to immunity for undisputed, bona fide "official acts". It's much broader: "conduct
alleged to
involve official acts."
We don't know what they mean by "alleged" (is "alleging it" all it takes to create immunity?) or by "involve" (does using a president's White House phone in the Oval Office to make an improper phone call "involve" his official acts?).
I'm more pessimistic than you are. Thomas and Alioto (and likely Gorsuch and Roberts) are already in Trump's pocket,