Withdrawals for Lido on Ethereum

So im by far not a tec-guy, but im interested in the section about the oracle-commitee, which is needed to fullfill a withdrawal request.

There are two approaches to using oracles: data can be brought on-chain and calculations can be performed there, or calculations can be performed by the oracles and the outcome can be pushed to the contract.

here are two approaches to using oracles: data can be brought on-chain and calculations can be performed there, or calculations can be performed by the oracles and the outcome can be pushed to the contract.

In general, these two approaches are equivalent in terms of the trust of the oracles committee, but the first approach would require performing the onchain calculations over unbounded data which is not practical due to limited block size and high gas costs.

For example, one of the proposed algorithms for determining the next validator to eject would require a loop over all active validators to find the next candidate. Unbounded loops will also occur when processing withdrawal requests.

Thus, a more practical approach here would be to perform calculations and data aggregation off-chain & make Oracles report the outcomes to smart contracts.

These oracles in the current state seem to bear certain risks of centralization.
As the authors state, the developers

considers this approach to be temporary and will work on a ZK-oracle that can perform the same tasks but in a trustless way.

What are the approaches to perform these tasks in a more trustless way? How far are these developements?
Anyone can elaborate on this?
For me, certain keywords immediately remindet me of Truebit. Would that possibly be capable of these tasks?