uBO covers most of uMatrix (and more).

Some of that uMatrix coverage is a hell of a lot harder/more awkward in uBO.

Basically every uMatrix user always also ran uBO too, for the more DOM/'content blocking' aspects (primarly 'cosmetic filtering' as it calls it iirc).

uMatrix lets me block all third-party, allow only first-party scripts/XHR/iframes by default, and then in two clicks (including opening the extension's popover menu) allow some specific host's scripts or whatever, while still blocking its cookies/frames/XHR/media/et al.

uMatrix is more advanced than uBO 'advanced mode', and just as easy to use; i.e. easier to use than 'dynamic filtering' or whatever people suggest that's buried in the full-page settings and not something I'm going to be doing 'on the fly' while visiting a site.

I still use uMatrix (and uBO!) and remain thankful for it - I just hope it lasts, not obsoleted by browser API changes or whatever. (nuTensor was forked to take on that burden, but itself now archived. Apparently - I read in another HN topic on this recently - because uMatrix actually did receive some maintenance update.)