How far along are you? You could finish your phd, then get a two year diploma in mechatronics, electrical eng, instrumentation. All near future proof and apparently pay well enough. You could even cert up in NDT, IRATA, ROV and that sort of thing. With your phd you'd get your foot in the door pretty easily.

I'm not very familiar with the employment environment at my place, but according to my senior the environment seems to get worse these years. I hope when I graduate I can still find a job with my phd degree. Thank you for your advice!