If you're looking for Video only, and don't really into macro video. Action cam would serve you well for the purpose.
There are 3 brands that dominate action cam market, GoPro, DJI, and Insta360.
I'm using Insta360 Ace Pro, which is kind out outdated model at the moment since they release Ace Pro 2 already. The benefit of Insta360 Ace Pro - or even Ace Pro 2 - is that there's a function called 'Clarity Zoom'. This is kind of Digital Zoom that crop into about 50% center of the screen. It would help you when you want to shoot somethings that's not 'Wide Angle'. It also come in handy when you want to add a macro wet lens and just use the center of the frame. Insta360 software also handle some color correction quite nicely.
The whole unit in housing can fit on your palm. So it's answer your need for small system, unless you want to add video light.
I have video on Youtube that partly taken with Insta360 Ace Pro underwater from my trip in early August. Will post a link later tonight. (I cannot access YT from my work network)
