Essentially, he was hailed as being the new Wizard/Keeper of the Rock of Eternity, stating he was "everything that Shazam was, but also everything Captain Marvel was." He kept his physical attributes and gained the ability to cast spells, teleport from the RoE to anywhere on Earth, etc. Lord Marvel's problem was that he was mostly implied and inferred power; technically he should have been around Shazam's level, but his lack of experience would make him less effective.
Bare minimum, he should be Trans level, though, as he's still at least as strong, fast, durable, etc. as he was when he was Captain Marvel. He was also "defeated" by Black Adam in the RoE thanks to Isis and some mitigating circumstances.