Sandbagging is reportable, which is what you should do if you feel this is taking place. The staff will determine if it is actually taking place.
sandbagging

Here's what I know. I have been ranked at about 1000 for a long time. When I play players ranked 900-1100 I win about half the time. But whenever I play somebody ranked in the 600s they almost always crush me quickly. That's sandbagging and it is rampant here.

Here's what I know. I have been ranked at about 1000 for a long time. When I play players ranked 900-1100 I win about half the time. But whenever I play somebody ranked in the 600s they almost always crush me quickly. That's sandbagging and it is rampant here.
You have played 4100 unrated games and only 64 rated games.
It seems likely you need to play a lot more rated games to get a true picture of your own ratings and ratings validity overall.
It seems like several players are playing with public ELO of 500-700 when they are really 1100-1200 quality.
Is that a thing?