Let's be honest here: IDEA's algorithm is crap. I lost ALL the games, 100% of the correspondence games where IDEA was involved. The way it does things is nonsensical and it's almost like it wants to generate evaluation holes where a strong centaur can play a move that IDEA missed and throw all the analysis done to the wastebin.
IDEA spends most of its time analyzing and extending irrelevant variations, and a good portion of what is left finding alternative moves for those irrelevant lines. It pays so few attention to the mainline because most of the time it'll not find it.
You can't really compare ChessDB's AI with IDEA, despite the low depth I've checked variations where CDB is able to outperform Stockfish Depth 36, and this is after one has to go to the leaf nodes that have nothing and do a "5 second request", just because reaching D36 is too slow so by the time it's done CDB will have built a tree.
What you would see in this CDB tree is that the main move of the main line has some 7 score (which corresponds with 0.07) while D36 shows some absurd 0.40, but if you play the variations against each other, some will regret its choices, and you'll have to go back and try something else. Eventually CDB's eval might have dropped to 14 (0.14) but D36's eval would have dropped to 0.28, enough to the root to have been refuted, because white had many alternatives before that were >0.28, and doing it like this can be much faster than having to play D36's moves from the black side, because it takes a while, CDB's tree moves are just there instantly.
And this is with CDB doing its thing while the line you request gets a fragment of the resources! Imagine if you could focus all of CDB's resources in the line you're interested it, it'd be insane, and surely, if you gave the same time and resources to CDB and to IDEA and they played a game, IDEA would lose every time, and it wouldn't matter what depth IDEA used, while CDB has already been optimized to D22 because other depths don't perform as well.
I think the main advantage strong centaurs have over such automatic methods is knowing when to use MultiPV and when stick to SinglePV, when to go wide and when to go deep. 30% of the time CDB has the main move wrong (initially) and on a portion of that the best move will not be in its top 8 (and it won't find it unless you play it), that's when I can outperform it, but of course I had already done analysis by myself to find the best move, and that took a while...