As to having a technical background
23 years as a mechanical maintenance engineer (fitter and supervisor) all mechanical systems, such as, hydraulics, gas turbines and electrical systems in military avaition maintenance fit the picture?
Yep! That would do the trick. It won’t guarantee you getting a start, but your technical training/experience is in line with what employers will be looking for.
Employers are not looking for people that have no tech background and have simply completed an ROV course at a school. Nor are the ROV crew offshore for that matter!