Short answer: yes.

Long answer: You can use the attestation app bundled with graphene to check the integrity of the system. The catch is, you need another phone with graphene os to do it properly. There is also an online attestation check, but IF the OS is purpusfully infected, you can’t rely on what the app itself says.

If I were you, I’d try to reinstall it. The whole procedure can be done from following instructions in amy chromium based web browser. grapheneos.org/install/web