How do I send parameters like role to next-auth at signup

[trufa]

I have what seems to be a conceptual doubt about where and how to implement user role logic in a next-auth app and which approach is the most conventional.

Namely when using something like this

providers: [
	Auth0Provider({
		clientId: env.AUTH0_CLIENT_ID,
		clientSecret: env.AUTH0_CLIENT_SECRET,
		issuer: env.AUTH0_ISSUER,
		profile(profile) {
			return {
				id: profile.sub,
				name: profile.name,
				email: profile.email,
				image: profile.picture,
				role: //HERE I CAN SET 
			} as User;
		},
	}),
],

This correctly sets up the role when hardcoded, the Prisma adapter is working too and I can get it all the way to the frontend with the session callback

callbacks: {
	session: ({ session, user }) => ({
		...session,
		user: {
			...session.user,
			id: user.id,
			role: user.role,
		},
	}),
},

What I don't understand is where to get this logic from, how can I send it to next-auth.

The only thing I can come up with is something like setting a cookie with the role, let's say I have two buttons one for customer signup and another for partner signup, before redirecting to /api/auth/signin I could set a cookie, but this is kind of ugly to do it next-js app router from the client side, and I seem to be missing something obvious here.

What is the most common/recommended approach for this? How can I pass the logic down to the options?