Yes Marvel has a Captain Marvel (not MAr-Vell, BOO!) and DC can't use the name due to Marvel having the trademarks.
Yet DC thinks Shazam is too close to Superman in terms of infringement.....
....which I can see to a point however there are differences between them too.
However money talks and Disney/Marvel have got money and successful movies unlike DC.
So perhaps the whole Captain Marvel trademark/ownership junk could now be resolved if DC receives enough cash? Bring SHAZAM as Captain Marvel into the MCU and comics.