There are no "DIAMOND 5 CLAMPING" problems

There's no problem at all.

It's just that you're bad and that's why you're stuck. I see all the complains of how Riot made master tier and fucked up diamond MMR. but then I see the WIN/LOSE % rating and i see a subpar 50%. There's no clamping problem. It's just the system working as intended.

However, there is a problem. The fact that bad people who clearly don't have the capacity to pass gold can even make it into diamond 5 in the first place.