I have a similar space, 18x24 2 car under garage with just over 7 foot ceilings. The white paint will make a big difference with the low ceilings.
I used the 22w Hyperikon light on amazon, 4000k, 2200 lumen, I think there were and still are about $60 for a 4 pack.
I used 20 of them, 3 rows...