If I know for a fact that a company is about to collapse and I establish a short position, will anybody notice? It depends on a lot of factors, but I could make an assload of money on puts without nudging the market.
Technical analysis is all about answering the question: are you able to filter who know something vs those that don't merely by looking at a buy signal? The answer: no, not really. Insiders acted well in advance of the SVB issues being made public, and there are lot of other examples of people making guaranteed bets that weren't obvious in the technicals. The noise is just too much.
By the time the signal is clear, the market has "priced" it in, and now you're just trying to predict the random actions of the know-nothing crowd.
Technicals are always after-the-fact. Since enough people with deep knowledge have to have already moved on that information in order for the market to have reacted to it.
It's much like trying to predict a fire by watching a crowd running away and hit the fire alarm. You didn't predict the fire and you can't have predicted the fire. Maybe you could have noticed one person booking it for the exit and follow along, but you still didn't know what was happening and were going on blind faith.