Even with a burner sim, there is the International Mobile Equipment Identity (IMEI) number, which is tied to the phone, and is known to all apps with the android.permission.READ_PRIVILEGED_PHONE_STATE permission.
As of Android 10, apps cannot obtain permission to access non-resettable hardware identifiers such as the serial number, MAC addresses, IMEIs/MEIDs, SIM card serial numbers and subscriber IDs. Only privileged apps included in the base system with READ_PRIVILEGED_PHONE_STATE whitelisted can access these hardware identifiers. Apps targeting Android 10 will receive a SecurityException and older apps will receive an empty value for compatibility. The currently enabled carrier-based messaging app for SMS/MMS/RCS is a special case that's given access to certain device identifiers including the IMEI. This is normally the GrapheneOS fork of AOSP Messaging but can be changed to another app by the user.
Since these restrictions became standard, GrapheneOS only makes a small change to remove a legacy form of access to the serial number by legacy apps, which was still around for compatibility. It used to need more extensive changes such as disallowing access to the serial number but those restrictions are now standard.
I don't know however if sandboxed google play is such a privileged app.
That can't be true? <https://grapheneos.org/faq#hardware-identifiers>
I don't know however if sandboxed google play is such a privileged app.