The problem is that pilot shortage is not exists. Also, it didn't exist in glorious 2017-2019.
Airlines had shortage of experienced high-sjikked aircrews (Captains, TRIs), not a newbies.
And now, as pool of unemployed experienced pilots is still pretty big, what is a reason for airlines to prefer fresh graduates over experienced pilots?
It doesn't make sense, to "play a gentleman" and leave "low-hour" positions to newbies, when you need to pay bills.
As well as Vietnam (or any other company, hiring expats) - they need expat aircrew for two main reasons:
1) Fill the gap in manpower, during shortage (basically, someone need to fly new Airbus right now, while local pilots are still doing their tratining)
2) Hire high-skilled pilots, who can help them to maintain proper culture and standards in Flight Operations, teach local fligtcre, etc,
Again - why should they prefer European low-hour pilot over local low-hour pilot?
My expectation - ramp up in 2023, when companies will start grow again and pool of experienced pilots will dry up. But you anyway can expect hard competition with thousands of fresh guys and girls just from flight school.