You've made a lot of assumptions that aren't true. Highly recommend actually researching them.
You can absolutely have price oracles of crypto assets without any interaction offchain, as you can use uniswap market prices and if they differ from any other exchanges arbitragers will make a profit by fixing that difference. But that is another oracle that is different from chainlink.
Chainlink is decentralized. It could possibly be attacked with enough effort and money to destabilize things but that is a totally different threat vector than the government restricting trading to services it doesn't like or censoring users.
Fei is backed only by decentralized assets.
UST was backed by nothing which is why it collapsed, Fei is over collateralized. You don't get any rewards for holding Fei.
Uniswap is only between cryptocurrencies. As I said earlier, those cryptocurrencies are either other stablecoins, or non-stablecoins. If it's backed by stablecoins, then it's centralized. If it's backed by non-stablecoins, then it's non-stable.
Chainlink is, from what I understand, a truthcoin-like system where oracles put down collateral. It is fundamentally a broken system because whatever group with the majority of the collateral just wins. What is stopping a government that can censor users and restrict trading from forcing oracles to collude and report false information?
You keep repeating that non-stablecoins make it non-stable but it doesn't actually make any sense. Fei is a stablecoin using non-stable assets, that is stable. All you need is a treasury bigger than outstanding debt. You're going to have to present better evidence than that.
I addressed your comment on Chainlink already, yes it could come under pressure or attack which would destabilize the network. This could be used to break many things, but it's not a vector for censorship / centralization because it has nothing to do with Fei's use as a currency and definitely doesn't make Fei centralised.
If it's backed by bitcoin for example, and you're trying to peg it to USD, then the spending power of your treasury in USD will depend on the price of bitcoin and the peg will just break when the price of bitcoin falls too far.
Fei's reward system is controlled by whichever party controls the oracles. You can outsource the oracles to a proof-of-stake-like system on chainlink, but that doesn't get rid of the fundamental problem.
You can absolutely have price oracles of crypto assets without any interaction offchain, as you can use uniswap market prices and if they differ from any other exchanges arbitragers will make a profit by fixing that difference. But that is another oracle that is different from chainlink.
Chainlink is decentralized. It could possibly be attacked with enough effort and money to destabilize things but that is a totally different threat vector than the government restricting trading to services it doesn't like or censoring users.
Fei is backed only by decentralized assets.
UST was backed by nothing which is why it collapsed, Fei is over collateralized. You don't get any rewards for holding Fei.