Note that the majority opinion forbids prosecutors from referencing the official act in court, no matter the charge. So they'd have to prove the President accepted a bribe, but never mention anything about the ambassadorship. How could a jury ever reach a guilty verdict? At most, the evidence would point to a President receiving a lavish monetary gift.

This isn't a misreading of the ruling. Justice Barret dissented from that particular part of the majority opinion, bringing up the hypothetical of bribery.

well that's insane

If you read footnote 3 it says the prosecutor may reference official records of the act. They simply may not reference the president’s personal records. So you are not really correct.

They just decided last week in Snyder v. United States that its only a bribe if you have clear evidence, and a suspicious gift is just fine and perfectly legal.

They essentially decided that with executives years ago with McDonnell v US

SCOTUS has repeatedly hemmed in the scope of bribery charges and expanded executive privilege. The only way to nail the president for a corrupt appointment at this rate would be:

Enter LOBBYIST and POTUS on CONGRESS floor

LOBBYIST: projecting voice I am now rendering payment in exchange my appointment as ambassador to Sweden. What say you?

POTUS: projecting voice Yes, I knowingly accept these improper funds and -

CONGRESS immediately gathers a quorum, impeaches, and removes POTUS mid-sentence

POTUS: - name you ambassador to Sweden.

Discussing the expectations of appointments with potential candidates is an official act as president and would enjoy immunity the same way that conferring to commit crimes with the DOJ does. It is theoretically possible that the dumbest person alive could get convicted but generally the latitude seems to be insanely wide.

How can you determine that the bribe was for an official act if “… courts cannot examine the President’s actions on subjects within his “conclusive and preclusive” constitutional authority”? In other words, if courts cannot even examine the official action, then what is the bribe even for? A bribe needs to be connected to an action to be considered a bribe at all.

You can't and that's the specific reason Justice Barrett concurred only in part.

They can reference the action. They just can’t examine the presidents motivation. But they could present evidence like “President X received $500,000 in cash from Mr Y as recorded on this video. Two days later President X pardoned Mr Y’s brother.”