I started shooting u/w video 15 years ago with a $1,000 budget which bought me a camcorder in an Ikelite housing, red filter, couple of 500-lumen lights. This was a modest sized rig which wasn't too difficult to travel with and produced ok videos.
I quickly graduated to a DSLR in a housing, dome port, flat port, several lenses, upgraded to a pair of 1,500-lumen lights, tray, strobe arms, etc. This was a gigantic rig that required its own carry-on sized pelican case for travel. It took a lot of work but produced excellent videos. Particularly, I liked shooting close focus wide-angle (CFWA). Total cost all in was >$5,000. Eventually sold that rig as I was raising a family and diving less.
Fast forward another 10 years...
I now shoot a GoPro 11 in the proprietary GoPro housing. I added a tray with flexi arms and a couple of 2500 lumen lights. Price <$600.
I followed Backscatter's instructional video on how to set up the GoPro for u/w shooting. It shoots videos that are every bit as good as what I was achieving with the DSLR rig.
I don't know much about the OLY rig you are considering, but I can attest that the GoPro is phenomenal.
Because I like to shoot CFWA, I am now seriously considering this upgrade which I suspect will yield even better results than my $5k DSLR rig, and all still under $1,000...
Backscatter Sharp Wide Lens Pro Package
Either way, with the camera technology today, you really can't go wrong.
Good luck and happy shooting.