Re-upping my post from 1.5 years ago on "layer 3s":

https://vitalik.eth.limo/general/2022/09/17/layer_3.html

The summary is that layer 3s don't magically improve throughput even more, though they can reduce some fixed costs of batch publishing and deposits/withdrawals.

@nuse thought this might interest you 

Thanks for the share, Vitalik!

Founder of Hydrate Labs - Writer, Explorer, Researcher, Arabic Language Enthusiast - Formerly @Comcast 

Vitalik has really written an essay about everything hasn't he