SQL Server should do just fine. I use Vitess (MySQL hosted on PlanetScale) with Prisma for my Next app, https://debate.land. It works just fine with scale, but I have found myself turning to writing some raw SQL queries to optimize performance/run some nuanced aggregations that Prisma doesn't seem to have a way to handle. If I had to do it again, I'd probably use https://drizle.team. Seems to be a more performant ORM. But for getting started, either will suffice.