runsongas
Contributor
Blackmagic has the pocket cinema (micro 4/3 I believe) that does 6k for $2400 MSRP. Maybe you could find one used. Dive housing might be difficult for that. There's a handful of brands selling 8k video cameras, but those are truly expensive.
housing and lens with port pushes the cost way up. same problem with the panasonic gh5.
@CaveSloth for that budget, you could look at the sony a6300/6400/6500 with the meikon housing and port. it would only be 4k30p though.