Other way doesn’t work as well flying LH from FRA via PVG to elsewhere.
When you arrive to PVG there is non existent/easy connection to your next flight.
you have to stay in a queue, pass immigration, collect your bag, pass customs, go out, find check-in desk, realise that they are not open for another few hours, free/wasted time, back to the desk and check in your bag, get ticket, queue, security, immigration, lounge/gate.
Lesson learned to avoid PVG as transit airport.