Guessing many here may have seen the ThunderTiger SeaDragon before but here is a recent video of it from CES. I think I’m correct in thinking this is all BR based on look of the tether, motors, and use of QGroundControl.
last year they actually showed a prototype using BR Thrusters.
Now they build their own ones.
Also the Tether was branded differently. The same for the other ROVs from China…
(See this posting: Underwater vehicles at CES)
They had a DWTek wet connector on one ROV (green tether), not sure if on all.