I've set up clerk (core v2) with next-on

import { clerkMiddleware, createRouteMatcher } from "@clerk/nextjs/server";
import { NextResponse } from "next/server";

const isProtectedRoute = createRouteMatcher(["/start(.*)"]);

export default clerkMiddleware(
  (auth, request) => {
    if (isProtectedRoute(request)) {
      auth().protect();
    }

    return NextResponse.next();
  },
  { debug: true },
);

export const config = {
  matcher: ["/((?!.+\\.[\\w]+$|_next)._)", "/", "/(api|trpc)(._)"],
};

const createContext = async (req: NextRequest) => {
  return createTRPCContext({
    headers: req.headers,
    auth: getAuth(req),
  });
};

            "message": "Clerk: getAuth() was called but Clerk can't detect usage of clerkMiddleware() (or the deprecated authMiddleware()). Please ensure the following:\n-  clerkMiddleware() (or the deprecated authMiddleware()) is used in your Next.js Middleware.\n- Your Middleware matcher is configured to match this route or page.\n- If you are using the src directory, make sure the Middleware file is inside of it.\n\nFor more details, see https://clerk.com/docs/quickstarts/nextjs\n",