I agree @shadey and I will keep looking myself too, I would love to build them completely.
I still think Rapid LED pucks would save some cash as well as some headaches due to the meanwell drivers built into the board, they are powered, cover 2x2 and only $50 CAD each. Looking doing this yourself first you would need to find a strip (which I haven’t in any reputable form aside from Rapid LED who sells individual COB as well -but only on their US site https://www.rapidled.com/solderless-cree-xp-e2-far-red-led/ ) then power it and mount it. After building the DIY array I would say that time is a factor that I did not accurately cost. Having something already in a strip form saved a lot of time, but wiring, splicing, testing and soldering is very time consuming. If one want to go that route you could do so with the COBs listed above, they would be easy to add to an existing setup and only $5 per COB.
I for one am still going with Rapid’s Emerson and Exotic boards from Rapid, this is the US site again