Nextjs with Express Backend VS Nextjs with their own Backend

I’m using Expressjs with Nextjs because it’s very easy for me I can use express middlewares very easily, and I can use all the express features, but personally I hat the Nextjs backend because it’s very hard to work with, there you cannot use the express features, so what do you suggest? Nextjs with Expressjs backend or Nextjs with their own backend?