Xin chào Phi,
The big issue wouldn't be your off-duty life. It would be the time travel you would do going from LH to VN.
The way they look at safety, crm, maintenance, mel, operations, rostering, rules and reg, training, etc, etc, etc.
Trời ơi!
You would take a trip 40-50 years back in time.
If you wanna check it out, take leave of absence, and go there on a contract, otherwise sit tight!