Cardano is a cryptocurrency that offers ~250 transactions per second but should soon scale without a layer 2 solution. I mention this as I run a validator on a 8gb raspberry pi with ZRAM swap enabled with no issues consuming ~5W the whole network could run this way if needed. This is lower power due to a mechanism called proof of stake. BTC uses proof of work. Ethereum has been 'trying' to migrate to POS for some time.
As for layer 2's this could partly be the solution to some high costs. But risks sacrificing decentralization.
As for layer 2's this could partly be the solution to some high costs. But risks sacrificing decentralization.