Some noob questions about BTC value proposition, market value, etc vs others

In no particular order:

1. Where does the fundamental value of BTC come from as opposed to any other digital asset? Everyone talks about decentralization, consensus, etc, but those are properties of blockchain and not the specific BTC asset. You could accomplish the exact same thing with ETH, XRP, LINK, DOGE, etc - the value proposition I feel lies in the blockchain architecture and not the specific coin being used in a blockchain fashion. Thus, I am not sure why BTC is digital gold, but not anything else. Is it simply the capped supply of 21M tokens (I think) making it deflationary? Why can't I just create a new coin XYZ that is also deflationary? Why won't that have the same potential to be digital gold?

2. What makes the prices move? I know reasonably well how supply and demand affects any kind of auction market: stocks, bonds, etc I know how the order book functions, and how limit / market orders work. I also know about the technical indicators (Bollinger bands, MACD, RSI, etc). My question is more what causes the price to swing one day and not another day? How does everyone agree that on XYZ day we're all going to start buying BTC and make the price go up? How come sometimes enough people want to sell that it falls back to the original baseline value vs sometimes more people sell and it crashes? There's not much fundamental going on to justify this I feel. Stock markets behave the same way, but at least there are fundamental drivers in the underlying companies