Ethereum does not use Proof of Stake, it is a proposed change that is being worked on, with a timeline of several years before it will be put into action, and that's only if the network accepts it.
ETH 2.0 has launched in parallel with ETH 1.X. The timeline is ~1 year for final merge, not years. This is potentially going to be accelerated (https://notes.ethereum.org/@vbuterin/B1mUf6DXO).
The "network" doesn't accept anything. ETH updates via hard forks. You either get on the train with the most support, or you don't. The majority wants proof-of-stake and there is already almost 4 million Ether staked on the ETH 2 chain (https://launchpad.ethereum.org/en/).
This is what I mean by the network accepting. Admittedly there's a spectrum of win/loss as per the ratio of the two resulting networks, but I'd suggest that the stake based network being substantially smaller would essentially be a failure, especially if the mining is still happening.