distinguishing manipulation or genuine price movement is hard though, can't really determine what really happen if we don't get any real data about who buys and who sell.
thing such as manipulation could definitely happen but I think it's only possible in a coin that has low trading volume since it costs less.
with BTC, it won't happen, even recent microstrategy large buys up of BTC that just happened recently only moved the price of BTC slightly, I don't believe there's any whale that could move the price, BTC recent price also seems natural and purely influenced by the news.
but if we look at CMC there are some low trading volume coin that suddenly got thousand percent of increase, it could just be a large spot buying or the project delivering some outstanding things.
It is true that Bitcoin manipulation is much harder than lower cap coins but that does not mean Bitcoin cannot be manipulated. Just a small movement like 5-10% is enough for whales to make significant profits, they don't need to find ways to manipulate to create 40-50% movements like shitcoin because they are using billions of dollars in bitcoin and 5% of 1 billion dollars is not a small profit.
If bitcoin is not easily manipulated, can you explain why bitcoin is so volatile with just 1 fake news spreading in the market? Remember the news about Mt.gox? Every time there is news that they are going to compensate investors, the market reacts and bitcoin gets dumped immediately and this has been going on for the past 10 years. What is that if not manipulation? A market that is so sensitive to news, even fake news, if that is not manipulation then what is?