13 Sentinels: Aegis Rim.
It's made by Vanillaware, who were the makers of the 2(.5)D side scrolling action RPGs like Odinsphere, Dragon's Crown on the PSVITA. Which, sue me, have been on my Vita backlog for years now. Unfortunately there's only a PS4 version out atm for Aegis, yay exclusives, would've liked a Switch version plx.
And holy crap, this is one of them hidden gems. This thing was released in Sep 22 this year, and already has an average 4.9 stars with over 400 ratings on Amazon (and Amazon reviews are notorious for slamming VNs for "not being a real game" etc. smh). Even VNDB averages a whopping 8.95 with only 126 votes. It's on sale on Amazon physical NA for 30 bucks.
13 protagonists whose stories all intertwine in an epic Sci-Fi mecha time traveling world ending saga. It's not a traditional VN with static sprites and backgrounds; I'd say it's more of an interactive adventure visual novel. IADVN or something. Dialogue will be displayed over the character rather than a dedicated textbox at the bottom middle, though thankfully there is still a backlog you can refer to anytime. Presentation is supreme, you can control your current protagonist in a vivid 2.5D environment: there will be cars driving and pedestrians walking in the background when you're in the city, trees/branches will be swaying from the wind, characters all have fluid, expressive animations even when idle. The world feels alive. Then you think about the most recent VN where you have static sprites and empty backgrounds and it's like man, this is the future!
Yes, the world is threatened by Mass Effect 3 Reaper wannabes and it's up to the 13 protagonists who are able to control their own personal mecha robot "Sentinels" to defend the universe across multiple time periods and yes I made it sound cheesy, but seriously the presentation of this game is top notch and gets you hooked right away. The story plays episodic, there will be 13 protagonists with their own shenanigans and the story progresses by shifting protagonists and perspectives until all of their paths eventually overlap. Every character has their own goals and motivations, relations and revelations, and every time you think you answer some questions, you get a new bundle of them in your face!
There's a real time SRPG gameplay element that's thrown in to compliment the adventure novel aspect. It's almost universally agreed upon that it's definitely on the weaker end of the enjoyment spectrum, but it'd be pretty hard for the 2.5D to show epic battles between the 13 Sentinels and the Reapers, and we need some gameplay to appeal to the masses so I guess that's that.