There is a sum that equates space (4"²)/watts.
But what likely to be more important is a couple questions first if you'll indulge me.
1.Have you got a set number of plants?
2.In the 4" ² space are you going to be flowering too?
3.Budget...?
Veg and flower use different parts of spectrum so if only for veg toll be choosing different lights.
I use 100w led units above each large (25L) pot for vegging. Double that for flower.
But if I was buying lights now, I'd go with HLG clone from China (£/€/$350 to flower a 4x4) try kingbrite on aliexpress: probably best bang for your buck ATM.