Layer 2 NFT minting that gets written to ethereum base layer?

I'm ignorant when it comes to NFTs, I just had a look at opensea and rarible for the first time in a couple of years. According to the docs opensea supports a bunch of chains, mainly L1s, but also Optimism.

Am I right to assume that roll-ups ought to be able to make NFT minting possible on layer 2s, while having the NFT written to the ethereum base layer, or am I completely misunderstanding the type of data that can be shared between layers.... smart contracts vs account balances and suchlike?

ZKsync has had an nft minting service for a while, not sure how it works.

If layer 2 NFTs are essentially native to/stuck on their specific chains, this would make the future minting of NFTs on eth massively expensive when the chain gets more usage.