Once successfully impeached by the House, and convicted by the Senate, you cannot never again hold public office - pardon or no pardon.
Looks like all that hot gas you are blowing out your wazoo just went up in a ball of flames.
Trump will never get impeached though. The House could be controlled by 435 Democrats and they still won't have the guts to impeach him. Unless they want 63 millions Americans to storm the Capital.