Once SafetyNet was brought to Android a decade ago the tendency has been clear - these freedoms are going to be restricted heavily.
Because how do you make sure it's the user who does those modifications, willingly and well-informed? That it's not a malicious actor, not an user getting socially engineered or phished? Incredibly difficult compared to the current alternative.
If it's not a software root of trust that provides an attestable environment like Android or iOS. It's going to be a hardware root of trust that provides an attestable hardware environment, like SGX. I can predict no other practical avenue taken. Unless the orangutan really forces a demonstration on how untrustworthy these environments can be and a lot of money and effort is spent.
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You can maybe, trust the user to handle it's own certificate in their own devices? Though I admit requiring attestation is probably a good default.