Personally I prefer natural, but there are some pretty good ones out there where there's an implant underneath but it's hard to tell because there are large natural boobs on top. There are also surgical lifts even without implants.
They are naturally supported with connective tissue made from collagen, so you can use scoopfuls of collagen powder to help lift them more. Pills are too small, it would be like taking a protein pill. Exercising the connective tissue without damaging it is supposed to help too, though there's limited info on this. Going braless normally but putting on a really good sports bra during vigorous activity is probably best. Or at the very least there's no evidence that a bra keeps them from sagging and the limited info we do have says the opposite.
You can also look up NBE forums for more ways to make them grow besides what you're doing. There's 40% saponin (high concentration) bulk shatavari extract powder on ebay which is one of the cheapest deals. There are also capsules of 50% saponin shatavari or fenugreek from multiple different sellers. Cycling pueraria mirifica and progesterone cream is popular too, especially for those who are already C+ cup to start like you, but it's better to go easy on those two and perhaps try 1 at a time before both. Etc. Check out an NBE forum for more details.