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.
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 algorithm, redirect rules compete with other block and allow rules.
> The no-large-media-elements feature can't be implemented as this requires to inspect response headers on the fly.
> There is no concept of exception modifier filters in DNR, i.e. csp=/removeparam= exceptions cannot be accurately translated to DNR rules. For a specific example, all the removeparam= filter exceptions from AdGuard URL Tracking Protection, meant to override the main $removeparam=utm_source filter, can't be converted to DNR. At best, those exception filters maybe could be less accurately be excepted using the excludedRequestDomains property of the main $removeparam=utm_source filter.
These issues are all fixable by acting as proxy and inspecting/modifying/replacing requests on the fly (in sync/blocking mode).
Which is why when the Chrome team finishes fixing these edge case tickets related to MV3 proxy features, there won't be major issues with uBO anymore.
Note that per its author himself, uBO Lite on MV3 already does the vast majority of the work uBO was doing on MV2, largely enough for regular non-power-users people.
https://github.com/uBlockOrigin/uBlock-issues/issues/338 has a more detailed list of issues.