As a long-time (43 years) fan of pre-Crisis, post-Crisis, early New 52, and Rebirth, my suggestion would be to branch the DC monthly publishing line into 2 distinct lines, by leaning heavily on the return of the infinite earths.
Have a “DC Extended Universe” line, comprised of many of the current titles and featuring all of the “everything happened” continuity under this brand, and with the current versions of our favorite characters on Earth-0, or whatever it’s now called. Basically, what we have today, but with a bit fewer Bat-books.
Simultaneously, launch a New 52-style “DC Prime Universe” line, comprised of a number of the classic characters but in rebooted, younger, continuity-free versions, that have their classic origins and are at the start of their careers. This brand would be situated on Earth-1, or Earth-Prime, etc. A clever storyline developer/architect could spin this new “earth” out of current continuity by having some event occur wherein these younger versions are cloned from the current legacy versions, in-story somehow. Much like Star Trek did with the Chris Pine cast.
Each line of comics would have its own unique cover-dressing that identifies which brand it belongs to. Conceptually, this wouldn’t be too different from the pre-Crisis era which had the current heroes on Earth-1, and their Golden Age counterparts on Earth-2, with the occasional crossover.
To me, this would allow DC to have its cake and eat it too, by satisfying both legacy fans like myself, and new-generation fans who are turned off by the myriad reams of continuity, and potentially increase sales and grow the audience a bit more.
I know Marvel has tried something like this in the past with some success, but I don’t think DC really has tried this, at least not quite to this extent. It basically takes what worked with the New 52, and past continuity, and allows them to co-exist alongside one another.