Yes, of course we need a yearly reboot of Superman and of course Batman. No. There is no way we’re milking this rotting, dead horse for any and all possible cash we can possibly get from it.
The last film appearance of Superman was Black Adam in 2022 and it was an (ill timed) post credits scene.
The last film to feature Superman was a year before that in 2021s Zach Snyder’s Justice League. Although technically this was an team up film.
The last film to feature Superman in the title was 2016s Batman v Superman: Dawn of Justice.
Additionally this new film isn’t expected to have Batman in it. Batman is not currently scheduled for this particular universe, although I expect he’ll make an appearance at some point.
The last Batman film was in 2022, simply titled The Batman.
So as you can see the horse is quite alive. Probably because the horse is named Comet and has super strength, speed and telepathy. Comet may not be in this upcoming film, but you never know with James Gunn.
Given the Supergirl movie is heavily inspired by Woman of Tomorrow, you might be right about Comet making an appearance.