You could own the safest, sturdiest, most secure & rugged offline crypto wallet out there - if you use it the wrong way, it's as safe as throwing some paper planes from a skyscrapper with your seed written on them.
Long term storage of the seed is a thing whether you have a Ledger or not. With or without the hardware wallet, you still have to write a seed somewhere and safely store it in case something ever happens to your device. The thing Ledger allegedly protects you from is that you can plug it into the most infected PC out there and even the roughest virus out there couldn't take your money off the Ledger without your physical approval of the transaction.
Moreover, if you ever wear your Ledger in your pockets and lose it, a thief would have only 3 tries to steal your device after which Ledger resets, protecting your seed and funds. But again, you still have to store a seed safely. There are a few ways you could do it, from the simplest & cheapest way to the more expensive Cryptosteel.
For example, if you live in a house you could write the seed on a paper, place it inside a small plastic bottle, close it properly and bury it somewhere in your garden - just make sure you don't forget the exact spot & nobody sees you digging & placing that bottle in there
For apartments, you could write it on a paper, fold the paper to make it smaller, place it into a little plastic recipient and hide it inside a pot. These are the simplest ways you could hide the seed and seriously - unless you make the hiding spots somehow obvious, no thief will break pots or start digging your garden.
