well, the most useless skills are Athletics, Acrobatics, Animal Handling, stealth, medicine, and intimidate, if you can figure out how to get those between background, monk, and 1 each of ranger + artificer skills, you have an almost universal brick because:
Athletics/Acrobatics are mobility skills, almost wholly personal.
Animal Handling is only useful vs beasts and monstrosities, and the DCs that matter require dedicated skillmasters.
Stealth is broken in the boring way and difficult to carry to the rest of your party.
Medicine doesnt have any functions at all
Intimidate can only get you fear responses