which project that you are talking about selling their coin ?, of course yes many coin/token price get manipulated by whale include btc ( i think )
Your thoughts are correct. All altcoins in this market are manipulated and BTC is like that, you can see the influence of manipulation in this market. Altcoins are pumped up and increased many times in a short time like BSV, or crashed many times in a short time like Matic ...