My apologies. I should have been more clear with what I meant.
I did not mean that 1 5000 light will give you better video than using 2 2800s. What I meant was that I would buy 1 x 5000, so that I could get another 5000 later. Using the single 5000 in the meantime would be somewhat of a compromise.
The thing with lights is that their penetration roughly follows the inverse square law. Meaning, to get the same illumination at double the distance requires 4 times as much light. Roughly.
Up to now, I have been using 1 x Archon D11V. That has 1 x Cree XM-L2 LED. So, it's rated for about 800 lumens. When videoing sharks down in NC, you can't even tell I have a light on until the shark gets about 2 feet from the camera, then suddenly their skin color changes from blue-grey to brownish.
Here's an example:
I don't know whether the Kraken Hydra lights put out a true 2800 or 5000, or if that is the typical "Chinese lumens" rating. I didn't go look up the specs on the COB LED emitter they are using. The D11V I was using in that video is rated at 1000 lumens, depending on what source you consult. In reality, it's anywhere from 300 to 800, depending on what other source you consult.
So, I figure if I were to upgrade to 2 x 2800 lumen lights, that would be roughly 6 times as much light. Which would extend my "illuminated distance" from 2'ish feet to maybe 5 feet? 2 x 5000 lumen lights might actually extend that out to 8 feet or so.
If you are shooting stuff that is further away than that 5 to 8 foot range, you might not get any real benefit from any of the lights you're looking at.
For underwater photography or videography, it's hard to have too much light. So, I'm in favor of always buying the biggest lights you can afford.
I don't have the budget right now, or I would have 2 x Archon D36V. Since I don't have that budget, I did recently upgrade from the 1 x D11V to 2 of the Evolva D02 at $37 each:
https://www.amazon.com/gp/product/B01FD3QQBU/
I haven't gotten to try them yet (in the water), but I figure they should be solidly double the light I'm getting from the D11V. 2X the light and 2X lights means 4X total light, which, hopefully will double the illuminated distance I'm getting now. I did try them at home and one Evolva is clearly WAY brighter than my D11V.
Anyway, I hope this helps.