The jewelry and industrial value of gold is minimal to its reserve value. Vast majority of gold is in form of bars sitting in national vaults. Zero intention of ever using those bars for jewelry/industrial applications.

Bitcoin's advantages over gold include

1. proof, security, and cheapness of reserves including greater protection from war pillage.
2. Cheaper and secure transactions. war, piracy, shipwreck proof. Divisibility is also a transactional advantage.
3. wealth escape options, including banking/sovereign failure and sanctions.
4. Cryptographic applications and protocol extensions including layer 2. But other crypto networks depend on bitcoin.
5. Better "tokenomics" than gold. Mining supply of gold increases when prices rise, and also attracts jewelry owners to trade in their jewelry for it to be melted. New reserves always possible finds.
6. Points 2 and 3 also make for faster and more secure banking system settlements. You don't need to rely on counter party bank not declaring bankruptcy for next 3 days.

Bitcoin is mostly USD backed?

No. You can buy bitcoin miners in bitcoin. Electricity costs are always charged in local currency.

There will never be a default on US debt unless it’s by choice. US debt is in US dollars, which the US makes. There will be inflation. Goods may end up being exchanged in another national or international currency someday. It won’t be Bitcoin.

QE worked last time because China helped QE by also buying up US bonds. A much larger QE with US at war/tariff war with whole world will put USD at a credibility crisis, if not in next recession then the one after that. Fractional banking is the real ponzi scheme, and a banking crisis, a property collapse that causes bank collapse. Colonial currencies are not an option to escape USD devaluation, unless they free themselves from servitude. Chinese policy has so far not embraced strong currency value. Bitcoin will always be protection from financial collapse/decline.