I hope this question hasn't been asked before.
I am looking for some examples where, say, the latest Stockfish or Komodo engine (or possibly some of the top NN engines) evaluates a position as plus or minus x for some time--possibly oscillating slightly near that point during that period--and then there is a big increase or drop in their evaluation.
What might be a suitable "for some time" period? I want to say more than a minute, but not more than 1 hour. Also, what is a "big" change in evaluation? I am not so sure about that, but let's say something like 3.0.
I am asking this question because, from my (very limited) experience, any dramatic changes in an engine's evaluation occur during the first 20 or so seconds. If an engine cannot find the deep tactics (or the deep positional play) during those first seconds then it is because the search tree has been pruned. (Am I right about this? I don't much about how chess engines operate.)
Edit: The drastic change in the evaluation should be a consequence of the introduction of a move not previously considered by the engine.