A real layer 2 would look more like something built on Ethereum (can see all its L2s at https://l2beat.com).
Essentially it's a separate network that every few minutes takes every transaction and compresses it into a data blob that it saves on Ethereum along with a proof that the computation was done correctly. The Ethereum L1 nodes then only need to verify the proof instead of re-executing all transactions that happened on the L2.
With this design users can go straight from an exchange like Coinbase onto the L2 and never need to use Ethereum, and fees are 10x cheaper because of the data compression. Fees will soon be 100x cheaper as Ethereum is adding extra space just for these L2 data blobs that is much cheaper than normal Ethereum data space.
Unfortunately it can't be done on Bitcoin right now because Bitcoin nodes don't have Turing complete scripting and so can't verify the proof that an L2 posts to Bitcoin.
Essentially it's a separate network that every few minutes takes every transaction and compresses it into a data blob that it saves on Ethereum along with a proof that the computation was done correctly. The Ethereum L1 nodes then only need to verify the proof instead of re-executing all transactions that happened on the L2.
With this design users can go straight from an exchange like Coinbase onto the L2 and never need to use Ethereum, and fees are 10x cheaper because of the data compression. Fees will soon be 100x cheaper as Ethereum is adding extra space just for these L2 data blobs that is much cheaper than normal Ethereum data space.
Unfortunately it can't be done on Bitcoin right now because Bitcoin nodes don't have Turing complete scripting and so can't verify the proof that an L2 posts to Bitcoin.