President can dissolve the Dáil at any time

De Valera did, and when he wrote the Constitution, he wanted to prevent a dictator taking over. He was president for 14 years and before him was a poet who did not understand much. It says in the bible, “the Lord giveth and the Lord taketh away”.
So when the president gives the seal of office to the taoiseach that does not mean he will be taoiseach until the next election.