Low scalability is a nonsense phrase that altcoins love to talk about. So what if you have bigger blocks and faster TPS? Eventually,,, you have to scale if you have more txs than your network can handle and that is a sign of success! BSV or BCH or whatever will never have this problem not because they can scale but because they will never have the success needed to scale.
AFAIK, higher scalability and higher TPS means faster transactions. Transaction speed is the problem Etherum is facing right now.
But I too don't believe depending on another blockchain would be beneficial to Ethereum. They should better hurry and bring up their updated blockchain.