Bitcoin itself is perfectly capable of storing its value in the long run because of its decentralization, and the fact that supply is limited, means that it can essentially imo be an alternative to fiat without the uncontrolled depreciation in the long run, even without a gold backed crypto.
Bitcoin's supply may be limited, but people don't realize that there are enough units for everyone to transact with. At some point 1BTC will be so much worth, that even one single satoshi will become a measurable value unit.
Don't forget that 1BTC can be cut into 100 million smaller units. If you do 100 million times 21 million you'll see that Bitcoin's limited supply won't form an obstacle or barrier when it comes to being widely usable money.
Bitcoin is not perfect, but it's capable of doing the job fiat used to do, but always failed afterwards because of how flawed the whole system is. If things play out in our favor, we'll see Bitcoin become what gold is today.