There are only two apps. Bitcoin/altcoins and then Ethereum. All supported coins use one of these. The hardware wallet needs an app for each specific coin though.

As for being afraid, don’t worry about it. You can move wallets between Ledger, Trezor, and software wallet if you know the seed words.

There is no risk of losing anything if your hardware is lost/stolen or chrome apps no longer supported. I am sure they will have a solution by then. If not then software that supports 24 word seed will be able to recover your wallets.