the wallet is a collection of public private key pairs. strictly speaking each time the wallet is used a new version is created (i.e. an old wallet.dat file cant derive addresses a new wallet creates) so best practice you should be backing up your wallet.dat file regularly
Discussion
storing a digital file has its own challenges which is why some users elect to use seed phrases and wallet descriptors instead as it offers some flexibility in terms of storage
keep in mind what you find comfortable doing now may not be the same thing a few years down the road
fair warning ⚠️ now I’m scared to try it. should i use one of these? a seed phrase or descriptors?
you should understand what both are and how they relate to one another.
a good way to practice is to generate a seed phrase, choose a derivation path, and try to recreate the same list of keys using Bitcoin Core (importdescriptors).
you should be able to do this without making any transactions 🧐