You can setup a separated account with a long password on MacOS and remove your user account from accounts that can unlock FileVault. Then you can change your account to use a short password. You can also change various settings regarding how long Mac has to sleep before requiring to unlock FileVault.
I didn’t understand how a user that cannot unlock FileVault helps. Can you please elaborate on this setup? Thanks.
With that setup on boot or after a long sleep one first must log in into an account with longer password. Then one logs out of that and switches to the primary account with a short password.