Lmfao, he's more knowledgeable than fugging Krayt, has access to the lore and holocrons of every major era and is a master of every way of the dark side and ritual lore. He's definitely in a top 10 knowledgeable Sith list.
This is the most knowledgeable Sith among a group who gave Darth Caedus a holocron they considered worthless, in jest of how shit Caedus' own knowledge was by comparison. The same Caedus who inherited knowledge from Lumiya who was an informal apprentice of Sith like Vader.
As you said before, there's a reason why Kyp wasn't chosen and Jacen was, it had little to do with power. Kyp's only renown comes from his ability to pick up big things with his Force gloves - something Vergere might not be aware of, other than that, he's a trash tier combatant who gets ragdolled by Kenth Hamner and shat on by a Vong Slayer. And Vegere is very far away from being one of the most knowledgable Force users ever
Kyp was dismissed for his unpredictability, whereas beforehand they considered both of them great candidates for Dark Lord of the Sith. A trash tier combatant, whose potential with the Force could make him more powerful than Darth Vader and had a simpler time TK'ing an object than the most powerful Jedi of all time.
An NJO era Jedi is inconsistent, well I'll be damned.