The video makes it sound like it'll double down on the high school side of Gridman. But Gridman was interesting for the contrast between the mundane and the toku/super robot parts, so I hope it won't just be a straight teen drama.
Either way it's nice to see Trigger work on a fully original anime after so long. Last one was in what, 2020?
As for what will happen to Gridman, it's hard to imagine the series without Amemiya or Trigger, and it makes too much money to leave it alone. Maybe they'll try to reimagine it into something completely different.