A short video showing how to farm Sundered Charms in Diablo 2 Resurrected.

1) You must be in Hell difficulty
2) You must have defeated Baal in Hell difficulty with that character
3) You must have Terror Zones enabled
4) Enter a Terror Zone (ideally Travincal, but the Catacombs works, too)
5) Kill Champions, Uniques and Superuniques. These have a chance to drop Sundered Charms in Terror Zones. The Council in Travincal is ideal for the speed at which they can be killed and the numbers of Champion/Superunique enemies you'll find each run, Andariel is a decent alternative for her high charm drop rate.