That’s a real problem, of course, but it seems fairly equivalent to any native app you install that can update itself or otherwise make a network request to obtain instructions.
Native apps that autoselfupdate have RCE vulnerabilities by definition and should be considered remote access malware already, before the developer release keys are compromised.
I am the reason Signal desktop now has a preference to opt out of autoupdate.
I agree with you. On the other hand, in the case of a native application, we can hope that the antivirus removes it. I hope that Microsoft has planned to update Defender accordingly.
That was my first thought as well, but I couldn't remember the name for that boundary. I hope there is a well-designed per-site control/setting/user consent system to keep tech support scam sites (or worse!) from adding one more tool to their arsenal.