What's the rival rank?

I'm level 154, rank Platinum 2.

Their prime was long ago, and now they're basically half-decent, completely washed up. If they had kept playing with shields up, they might have reached Platinum, but since they didn't, they're still stuck in Bronze, a washed-up player 1 passing by.

I'm Silver 1 and I suck at Rivals... ㅠ

Can you not play ranked if you're not level 100 these days? When I used to play, it took forever to climb to Diamond, gaining like 4 points at a time.