Which system integrity protection are you worried about missing? Muse being able to exfiltrate the contents of your messages db doesn’t compromise system integrity to begin with. It being able to write arguably does, but this whole conversation was about how to grant it full disk access in the future anyway.
And OP had SIP enabled, but his system still got compromised with a remote exploit.
And OP had SIP enabled, but his system still got compromised with a remote exploit.