Yes, divine charms are they best you can get.
There are a couple merchants in Aleroth in FoV/DKS who can sell divine charms. In D2:ED, or that section of DKS, you will have to rely on found charms.
Lancet's
guide for D2:ED lists all the divine charm locations in the original release, but as far as I can see, the
DKS FAQ/Guide only mentions the Gremory Family Chest in the fjords and a couple merchants in FoV.
FWIW, in D2:ED I had 8 blessed and 8 divine charms at the end of the game. In DKS I finished with 56 blessed and 61 divine charms (7 of which were vitality, 3 spirit, 10 strength, 7 dexterity, 6 intelligence and 28 other). I didn't use any charms in either game.