Why are teammates so braindead?

It really feels like im playing valorant competitive here.

i went through the first 30 wins with only 5 losses with an amaze mighty miner log bait deck.

All players with me had incredible synergy and it felt genuinely fun to play.

The moment i reached ranked ladder, every teammate I've played with have ZERO braincells. It's like they're just plain stupid or have never played 2v2 ever, even though they supposedly have cleared the 30 wins required to reach ranked.

Have you guys gone through this as well?