MBP 2016 Catalina. (The issue started when I attempted to upgrade to the most current Catalina version. I even erased my entire drive and upgraded to Monterey. But nothing helped. Restoring my backup didn’t help.) Had the same issue and honestly been pulling my hair out for over 2 weeks. I spoke to Apple support for hours, they apparently even connected me to senior support staff. And time and again the same error “Critical Software Update…” message. I did everything over and over, trying different steps as I kept finding suggested solutions. But this afternoon, I kept trying and restoring my old backup (Catalina), and this time after it restored and went into “completing restore..” I had selected no internet connection to this MacBook and also removed my USB and lo and behold it worked. I was back and working. But I must admit this software related and Apple needs to address it. Cause how does it end up working after so many days? Perhaps my HD was not configured correctly before, not sure. I am not techy...