@Brechtpd i commented your name where i'd need help. Currently it verifies everything.. So for example it verifies the first block after it is proposed.

First because of the blockHash, while i use metaHash, but also, since i used this: bytes32 blockHash = blk.metaHash;... i dont get why the first block state.transitions[blockId][blockHash].blockHash == bytes32(0) equals to true now.. (since i set the metaHash as blockHash)

            if (
state.tansitions[blockId][blockHash].blockHash == bytes32(0)
                    || block.timestamp < state.transitions[blockId][blockHash].verifiableAfter
            ) {
                break;
            }