Looking for work

Ask yourself "What can I do that the local people cannot do or cannot do with full proficiency."  The oilfield guys seem to do OK, as do some in IT.  As far as a bartender job, you may have to open your own expat bar.  Maybe there is something for you at one of the international chain hotels on the beach strip just south of Da Nang, particularly if you have worked for one of the same firms before.  The usual local drinking mode not a bar per se but a place with seafood, and mini chairs and tables with service by 18 year old cuties.  They are addressed by customers as "em ơi" meaning "my dear" or "sweetheart" and are paid almost nothing.  I don't think you fit that mold.

Find that sweet spot and you can do OK, but avoid competing head to head with locals in the labor market.