I’m new here so I don’t have much advice to give, but when my buds were in their prime, I added some bloom nutes in small quantities over time, cutting off the nutes a couple of weeks before harvest. and that did the trick. It wasn’t any specific type, just a generic 20-20-20+TE that promotes both veg and flower. This is not ideal (you probably want something with less nitrogen and more phosphorus for flower) but this is what I had access to from a local shop.
I guess with your new lights you should definitely see better growth. Make sure you get your timer right with 16/8 during veg and 12/12 during flower, otherwise you will likely get irregular or smaller buds. Make sure there are no light leaks into your grow site! Maybe read up on LST or FIM/topping to create more bud sites and distribute plant growth to get the most bang for your buck from your new lights.