A newly launched full Proof of Stake (PoS) ethereum testnet, Kiln, is now processing more transactions than the ethereum network itself.
1.3 million transactions a day are currently handled by Kiln, while ethereum itself is processing close to 1.1 million transactions. Parithosh Jayanthi, an eth2.0 developer, says:
Source: https://www.trustnodes.com/2022/05/31/ethereum-merge-testnet-surpasses-mainnet-in-transactions