@Keneda uFirefox is still far from having an android-style mobile experience, although the work must be commended. As the developer said on Gitlab, there are many gaps to fill : https://gitlab.com/debclick/uFirefox/-/issues/1 .
Yeah it seems to be random every reboot.
You can delete the url dispatcher config of other browsers but for Morph, it's in the readonly part of the system.