Just my ¢5 as I have been (still am, sort of) in the same situation. Few years ago I went from a gopro, which I was very underwhelmed by, to a Sony a6000 (around $450 with the kit lens) combined with a meikon housing ($120) and dome ($90). My willingness to pay for housing was always quite limited. With the risk of ruffling some feathers around here I never understood paying thousands of dollars for what is basically a plastic box to store a camera which will become tired if not obsolete in a few years time. Also I don't live in a place where diving is any good (Sweden at the time, Ivory Coast at the moment) so the cost per immersion becomes quite high. Never had any issues with the Meikon housing. New players entering the market has been glorious, which also goes for lights. I bought 2 x Hi-Max V11 2400 lumen ($300 total) excellent quality which have hold up very well. Of course there are much cheaper and brighter options available today. All this fit on a second hand rig with flex arms ($50 I think). I later upgraded with the Sigma 19 and 30 F2.8 (around $150 each) which fit the housing without vignetting and are remarkably sharp for the money, and the Opteka 67 mm 10x macro converter ($20). Note that the latter is not intended for uw use but actually works without any leakage so far. Very sharp.
You can check out some videos for reference here: https://www.youtube.com/channel/UCrTXKkItV4a3DR3TCw-9M4g
While the visibility were terrible the nightly close ups of fish in the video from Sudan (3:30), and the daily ones from Egypt (10:10) are probably a good example of what the Sigma 30 and 19 can do.
Of course the Sonys have a major flaw come uw wb which is noticeable in many of my videos and something that may refrain me from buying Sony again. I also shoot stills above the surface so this was another consideration and one reason I might co for ff when I upgrade (probably in the near future).
Anyway hope this is to some help.