for whatever reason, bitcoin is not gambling. Let me give a simpler example, if you buy gold will the price remain the same as when you bought it? Of course not, the price will change by around a few percent, whereas Bitcoin, due to its decentralized nature, has very drastic price changes. if you have the goal of buying Bitcoin for trading activities then your benchmark is price, but as long as you don't sell at a loss then you don't lose anything.
In my opinion, gambling activity is a process of multiplying money that is based on luck, but bitcoin is not like that, forever 1 bitcoin remains 1 bitcoin, only those who try to make a profit use DCA in bitcoin investment.