51% ETH attack

So with ETH now being proof of stake, and already >50% of staked eth being held by only 4-5 entities, how safe is the network if these entities liquidate their position and make way for other potential bad actors? Or if bad actors stake enough to makeup 51% of staked eth? Or any other number of possible situations in the future?

I understand it’s possible to burn these peoples eth if they abuse their power but who would be the judge of abuse and would they be able to prevent an attack from happening fast enough before real damage is done?

Eth is seeming more centralized than ever.