Enhancement core only has few places to get. Gunsmith bounties, quite tedious and you need 3 chars to get 12 cores a day. Nightfall, dismantle leggies and consumable which is quite expensive. For new light, crafting is near impossible. I have tried out with an alts. Man, it is brutal. Back to main and it is day and night. Play Terminal with cheese two free chests will give you plenty of shards. Tedious, for sure. That is D2. You need to grind a lot for new light.