WhoTheFuckisAlice This password is not the key for the encryption of the user data partition in every profile?
You'll want to read this section of the website about how all that works: https://grapheneos.org/faq#encryption. Here's a relevant quote:
Sensitive data is stored in user profiles. User profiles each have their own unique, randomly generated disk encryption key and their own unique key encryption key is used to encrypt it.
And another:
Using a secondary profile for regular usage allows you to make use of the device without decrypting the data in your regular usage profile. It also allows putting it at rest without rebooting the device. Even if you use the same passphrase for multiple profiles, each of those profiles still ends up with a unique key encryption key and a compromise of the OS while one of them is active won't leak the passphrase. The advantage to using separate passphrases is in case an attacker records you entering it.
https://discuss.grapheneos.org/d/5731-bug-fingerprint-unlock-disabled-after-profile-change
https://github.com/GrapheneOS/os-issue-tracker/issues/1611
I didn't realize that this was still a problem that people were experiencing. I used to have this issue from time to time, but not anymore. I can understand that this is very annoying, especially when using really long passwords.