Hello again pathfinder76,
In either case, 1Password hands the control over to Windows Hello. So a rogue piece of software could mimic the Windows Security prompt. The TPM is, in short, a secure place to store those keys and allows for 1Password to unlock with Windows Hello and persist through reboots/restarts.
When the TPM is not enabled Windows Hello becomes enabled when you unlock 1Password for Windows with your account password for the first time after you boot, reboot, or had completely exited the desktop app. This generates a new temporary unlock key to use. When you click the Hello button, we send an API call to Windows to confirm you are who you are, same as if the TPM is enabled.
Bottom line, it's best to take all reasonable precautions with your device to ensure it is free of malware and you trust the software installed. If you have further concerns, I've included our guide About Windows Hello security in 1Password for Windows.
Let us know if you have any other questions!