The firefox private window seems to work better than the chrome incognito mode. Maybe brave would be even better because I tested brave against fingerprinting libraries once and it was the best at avoiding any detection.
Deeply paranoid people can have occasional good arguments mixed in with their sociopathic traits. The fact that Brave didn't fork Firefox, or build their own like Ladybird implies to me that they are not really trying to improve the system. It's like Windows users extolling the virtues of the LTSC version.