Pre-Covid experience below:

XMN turnaround requires MAAS (meet and assistance), local ground crew will help you through the process but you need to go through CIQ (custom, immigration, quarantine) check for arrival and then return from landside and do CIQ again.

Process is:
Arrival Quarantine
Arrival Immigration
Arrival Custom
Landside
Go upstairs
Departure Quarantine
Departure Custom
Get boarding pass - they will print it before gate close so with MAAS you can get it even if you are late
Departure Immigration

i suggest you giving CX XMN a call and ask, I think it is possible again now as the process almost return to normal except for the black code part