Note that passes UAT could actually be nearly enough if UAT are properly written, your merge rules are strict enough and you do a minimum of complementary testi

Note that passes UAT could actually be nearly enough if UAT are properly written, your merge rules are strict enough and you do a minimum of complementary testing on release. The issue is that the people writing the UAT generally have no incentive to write good UAT. They want to ship. They don't want to get code blocked because it doesn't meet requirements. Amusingly and to get back to the core of the discussion, AI is generally pretty good at helping write good UAT.