Then you download and verify a reputable open source wallet such as Electrum and import your seed phrase or private keys in to it. It will then generate same addresses you had on your hardware wallet and give you access to the same coins. This just isn't very secure since you are exposing your keys to an online environment.

If you can't acquire a new hardware wallet and you want to maintain a similar level of security, then you would import your seed phrase or private keys to a wallet such as Electrum on a permanently airgapped (i.e. no internet connection ever) computer. You can then take the addresses from that airgapped wallet and use them to create a watch only wallet on your main online computer.