Although, the bitmex is only at half a billion dollars but that's still a big volume in my opinion. So your only choice is binance or mexc its up to you op.
It's not "only".
Actually, that's already big and bitmex has been known there mostly first before any others. But with some issues that have found in the past, that's how they've started to drop in volume.
Anyway, it's still a good one if ever someone like OP will put futures money that ain't much.