Devices that need access restrictions without network connectivity have to use something to protect credentials. You can't hand wave your way out of that.
That being said, for these cases you could use Argon2 which is mostly (entirely?) based on ARX constructs and will work well on embedded/underpowered devices
There are also some symmetric encryption shenanigans that can be done, but if you can use something other than password-based auth you're free from pretty much all of these problems, with probably much better security