To mine bitcoin you need to buy an asic, which is a single purpose physical good with at most two original maker (fabs). It needs to be physically received. This single distribution is trivial to track by the authorities and makes bitcoin mining a permissioned system.
Energy use is so large mining at any non-negligible scale anonymously is impossible. Any serious miner will have to open a company, move to a special facility and get a special energy connection. Mining only makes financial sense in few countries with cheapest energy. Last but not least, due to the difficulty mechanism mining for anyone but enormous miners requires pooling with others.
Pools are public entities that are yet another possible layer of control by regulation. Adding all that and the conclusion is that PoW has zero resistance to regulations. China could take over bitcoin, but they decided to throw away mining instead, only making it possible for America to do so in turn.
All it takes is indirect or direct control over >50% of hashrate to censor anything. It's not possible to create a fork without censoring miners, because any minority fork can be trivially attacked in an adversary situation. If any PoW network even becomes important for American government to try to censor it there's no defense.
To stake in ethereum, you need to buy eth, which can be trivially bought anonymously from anyone that owns eth, most likely fully online without any physical contact. A more permissionless system isn't possible. There's no physical trail, both from ordering asics and from energy use. All that's needed is an internet connection. Staking can be easily fully anonymous and can happen anywhere in the world. That's why PoS is the only way to have a decentralized network.
It's always possible to fork with any arbitrary subset of validators, whether for censorship reasons or other disagreements.
PoW is objectively worse than PoS in literally everything but as a method to distribute coins. Mining is a way to sell coins for energy and hardware cost, which is an advantage at the cost of being worse in everything else, but only in the early period.