Kibi This thread may be of interest: https://discuss.grapheneos.org/d/19832-is-grapheneos-moving-towards-a-stateless-system
Only a Factory Reset of the device will guarantee all traces of deleted files and user profiles. So if you have an extreme threat model, user a separate GOS phone that you factory reset each time.
Alternatively, you could operate as you describe, and then factory reset every week or every month. Since the main threat in this regard is an adversary getting physical access to your device to then performing forensics.