Visa free transit

Hi, I'm Indonesian. I plan to back to Indonesia via China. My flight itinerary is as follows:
- Vladivostok - Yanji (transit in Yanji 5 hours 20 minutes)
- Yanji - Shanghai (transit in Shanghai 19 hours 10 minutes)
- Shanghai - Indonesia

I will not exit the airport in Yanji, but I plan to explore Shanghai during my transit. Should I make a visa? or can I use visa free transit? Thank you 🙏😊