re: Worst modern President

Rank them in terms of damage to the USA:
#1 Biden - and he isn't even finished yet
#2 LBJ - escalated Vietnam, Great Society programs, Court appointments
#3 Obama - Healthcare system, deficit spending, broken ally relationships
#4 Carter - Never saw leftist idea he didn't like. Poor judgement, tax rates, court appointments

They all have the similar fatal character flaws that manifest in different ways: extreme arrogance/ conceit/ lack of humility/ over confident
Biden: is a career BS artist, pathologically dishonest, amoral, sociopath, lacks true empathy for anyone

LBJ: intelligent, dishonest, thought he was the smartest guy in any room, won his Senate seat with a ballot stuffing scheme in Texas

Obama: Gifted speaker, persuasive, Marxist ideologue, thinks he is the smartest guy in any room

Carter: Not very smart, condescending, naive, over his head, but had good intentions, poor judge of character, never learned from his foolish mistakes, easily manipulated by the left. Got elected because nobody knew him, was an idiot governor of Georgia.