I think the OP can’/don’t want to use cloud based accounts on some devices. Since the change, on iOS 1P can only create new vault when signed in with a paid 1P account.
It was implied by the response that he was using a free option.
I'm sorry for the trouble. 1Password no longer offers a free-to-use option on iOS. It can either be used with a 1Password membership account or it can be synced to a standalone vault created by 1Password for Mac or 1Password for Windows. It wouldn't be possible to create a new standalone vault from 1Password for iOS. Standalone vaults still work, but must be created by a licensed product (1Password for Mac or 1Password for Windows).
Actually no. It’s the same for paid users on ios. If it’s a the one-off payment IAP user, then there is no way to create new vault anymore. If it’s subscription user, the user has to sign in to the 1P account to create a local vault, which the OP might have good reason not to sign in on some sensitive devices.