I’m starting a new project and I’m hesitating between trying NextJS or staying with React + Express (my comfort zone).

My project is a webapp (as part of a teambuilding game).
In my project I would need to have a section for users to register.
A section for game participants, and another section for facilitators. So I’ll need to be able to filter the routes to manage the different authorizations.
I’d potentially need a websocket (on the participant side), but I’m looking for other solutions so as not to need one (so don’t necessarily base your conclusion on this point).
There will also be a scoreboard on a public route.
And finally a management section, so you can create/manage events (an administrative tool).

Initially, I thought I’d make an SPA for each part of my project (one for participants, one for facilitators, one for the administrative tool) and serve them via a Node server (Express) that would also act as an API. Then I read the NextJS documentation and browsed various posts, and I can see the many advantages of using NextJS (despite the fact that I’ve always been reluctant to use Frameworks other than Express).
So much so that now I’m wondering whether this might be the right opportunity to get my feet wet in NextJS and SSR.
I understand that with what React and NextJS have been doing lately in terms of rendering, SSR rivals SPA (suspense, partial rendering, etc.).

So here’s my question, in the context of my project.
Should I go for NextJS and make an SSR application?
Should I use NextJS, but make different SPAs accessible via different routes?
Or do I forget about NextJS and make my different SPAs that I serve via a classic Express server?

Many thanks for your help!