I had a firm belief in BTC that it could not be used in the Pumps and Dumps Scheme because of its scarcity (limited supply, high demand) and decentralization.
I think that in reality nothing is really free of pump and dumps.
But for bitcoin pump and dumps attempts can get diluted by arbitrage and the fact there are a good number of CEX, DEX and OTCex all competing, so they (P&D) do need big effort.
I've read Mt Gox did that. Social engineering (news/FUD) together with sudden movements in order to trigger small trader safety nets (stop loss and maybe others too), maybe together with some wash trading (most pretending it never happens) can be seen as the modern P&D. Are they so big and happen so often? I don't think so, hence there's not so much to worry about.