Earlier quoted context omitted.
The MV3/UBO issues are not really at all related to this ticket or GUI. The thing people take issue with is the removal of a number of mechanisms for intercepting and blocking traffic that uBlock Origin uses. https://github.com/uBlockOrigin/uBlock-issues/issues/338 has a more detailed list of issues.
If you have a look at the bottom of the discussion in that link: > The redirect-rule= filter option is also not compatible with DNR redirect action due to differing matching algorithm. In uBO, redirect filters do not compete with block/allow filters, as the redirect directives are looked up only after a network request has been matched to a block filter, whichever that is. This works differently in the DNR matching a…
That is not possible in MV3, and is the center of the entire problem.