ETH vs ETC: Decentralization, censorship, and PoS/PoW — where am I going wrong?

Hi, I'm relatively new and I'm trying to understand the issue of decentralization on Ethereum since the switch to Proof-of-Stake.

I sometimes hear Vitalik talk about future goals (“even more decentralized,” “censorship resistance,” etc.). At the same time, I read criticisms saying that block production on ETH could be influenced by large entities (exchanges, liquid staking, institutional validators). So I'm wondering: is the main risk today technical (the protocol) or rather economic and social (concentration of stakes, user habits, regulation)?

Conversely, Ethereum Classic has remained Proof-of-Work. I'm trying to stick to the facts: PoW may seem more “permissionless” (you mine if you have the hardware), but PoW can also become centralized through pools, ASICs, energy geography, etc. So I don't know if PoW "solves" centralization, or if it just shifts the problem.

My questions:

1. On ETH PoS, what are the concrete points of centralization/censorship today (at the level of validators, MEVs/relays, staking, exchanges, etc.)?
2. What is already being done (or planned) to reduce this?
3. Is PoW (like on ETC) actually more resistant to censorship in practice, or is that a myth?
4. In what scenario could ETC serve as a credible "backup"… and why isn't this scenario happening already if it's so obvious?

I'm open to corrections: if I'm confusing concepts (scarcity/currency/usage, PoS vs. PoW, etc.), please let me know where.