Yeah, its possible!
I see 3 diodes per LED and a current limiting resistor on each LED so its probably really 12v drivers but I would check that additionally because I could be wrong and you still need to know how much current they have. If its 12v you can use Alibaba/Aliexpress 12v flexstrips with Samsung LM561c or LM301b LEDs. I know
@VegasWinner has used them but it seems he deleted his account.
Let me see if I can find them, I will let you know.
Solution 1
These are COB's available in 12v and 32v and in 3000, 6000°k and Fullspectrum(1590°k). You need the 12v ones! And please, don't use the 110/220v ones with integrated driver, they flicker like hell and have bad efficiency. I would try it with 2 COBs in parallel on each driver, so you need 10 of them.
You could use 4 coolwhite and 6 fullspectrum chips or simple use 10pcs in 3000°k. Should work but use only one type per driver(2x coolwhite or 2x FS on each driver, not 1CW +1FS, even with the same circuit design the voltage could be slightly different because the thicker phosphor layer means FS COB's run a little warmer and therefor have little less voltage, same like CRI80 and 90).
https://www.ebay.com/itm/1X-50W-white-light-COB-chip-DC12V-32V-Integrated-Smart-IC-Driver-220V-110V-lens/332734653834?_trkparms=aid=222007&algo=SIM.MBE&ao=2&asc=20160323102634&meid=b099b971da0a4c86b9c59f7b7f73452c&pid=100623&rk=2&rkt=6&sd=263729107833&itm=332734653834&_trksid=p2047675.c100623.m-1
BUT, I would still order a cheap multimeter. Somethink like this should be enough.
Max. current of such COB's is 4,2amps and the sweet spot is probably around 2,2,5amps. Your 200-300w drivers are probably only 50 or 60w(5A) so two COB's in parallel would mean they run around the desired 2-2,5A.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=multimeter+DT830B&_sacat=0
These are not the best COB's you can get but it's at least the 2nd generation and the 12v ones use 120 diodes. Compared with gen1 thats 2,4 times as much and should make them at least 10-15% more efficient.
Solution 2(~8 times more costly)
Are the 12v flex strips like mentioned above. LM561c is a 200lm/w diode and even with resistors they are much more efficient. Such a 12v COB in coolwhite is probably 120-130lm/w at 2-2,5amps, with LM561c flex strips you can expect at least 150-160lm/w maybe up to 170. You need to order anyway from china..
https://m.alibaba.com/product/50041414537/Original-Samsung-LM561C-LM301B-led-grow.html?subject=Original--Samsung--LM561C--LM301B--led--grow&spm=a2700.7724857.normalList.10.6e581132zdlIlI&detailId=50041414537&redirect=1
You need 3 rolls á 5m (the 120 LED/meter version) and you need to cut them in 30pcs 50cm pieces and connect each 3 strips to one driver (in parallel). A hell of a soldering job but you don't have to worry about the temps. Costs much more than 10 gen2 COB's but would be around 160lm/w.