In its services and repair terms and conditions, Google says it will keep devices sent in for repair if they have a non-OEM part.

Update:

Google changes repair policy after criticism of third-party parts ban Google previously said it would not return mailed-in devices using “unauthorized” parts.

Source: https://arstechnica.com/gadgets/2024/06/google-changes-repair-policy-after-criticism-of-third-party-parts-ban/