the PS4 DLC has a delay of 2 months because more testing is needed with the extra songs and the new module (for every new song they have to check every single combination of hairstyle/accessories/modules, so is normal it can take lot of time), but i'm confident the release might happen around May/June, if not earlier :)
and about the new project, Makoto Osaki (producer of the Arcade team) said that they already have some ideas for the future, but they don't want to rush things and want the sequel to comes out naturally :)
(and before the sequel, they still can release new songs and new modules for MEGA39s and Future Tone PS4, for example Project DIVA X songs/modules, Project Mirai songs/modules, all Magical Mirai songs/modules, Snow Miku theme songs.. (❁´◡`❁)
the home DIVA team was busy developing the Sakura Wars game for PS4, it released a couple of months ago in Japan (and it will arrive in the west on April 28, you should all check it, is a very beautiful game and is easy to "see" that is has been made by the DIVA team, is has that magic charm ^^), and now they are developing a new secret game hehe who knows ^^
Sakura Wars - Take the Stage to Win the War 04.28.2020
games.sega.com