This is a succinct summary for everyone:
The president of the United States enjoys absolute immunity from many lawsuits while in office; it is legally untested whether they also enjoy criminal immunity from arrest or prosecution. Neither civil nor criminal immunity is explicitly granted in the Constitution or any federal statute.
The idea that a President can commit a crime (insurrection etc. is a federal crime) and be immune from prosecution is so stupid I dont know why some of you are pushing this immunity bullshit. Immunity from lawsuits is not the same as immunity from criminal prosecution.
A good example is police being immune from lawsuits (people sue the city instead) but they are not immune from criminal prosection (George Floyd's cops anyone).
A president is not immune from being prosecuted from a crime. Impeachment is not a criminal trial, it is a removal from office process, it has no weight on criminal conviction even if someone is impeached because of a crime, they would still have to be convicted of that crime.