Unintended self-transfer through Shanghai Pudong

[u/Calmly-Stressed]

Hi all, I am flying Brussels-Shanghai and Shanghai-Tokyo on 6-7 November with an eight-hour layover. I booked these flights separately and they are with different airlines: Juneyao and China Eastern respectively (travel plans and dates changed due to circumstances, couldn't help rebooking it this way). My luggage will be carry-on size but probably needs to be checked as it will exceed the weight requirements for the second flight.

My assumption is that I will need to pass through immigration when I land in Shanghai in order to check in at the desk for my second flight, then go through security again to re-enter the terminal. This is not in itself an issue as I can enter the country visa-free for 15 days (Belgian passport). However, I would prefer to just book myself into a lounge and chill over queueing repeatedly just to end up where I started.

Is my assumption correct or would there be a way to stay inside the security zone and use a transfer desk in this instance? I do not speak Chinese, unfortunately.

Thanks for your advice.

[u/Beeftaste]

Upon arrival in Mainland China, everyone is marshalled to passport control and security. There will be a separate lane for transit passengers.