C/E (limited) to QMED? Great Lakes or Oceans. Ships or ATB's?

Hey! My first post so im new at this. Im just basically reaching out for info and guidance. Im a Chief Engineer for a large OSV company. Im a American citizen but im working in South America and things are alright at this time.
I hold a C/E (limited) Oceans, Near Coastal and Great Lakes. In the last 22 years i have worked for 2 companies mostly. I worked ship assist tugs for about 8 years and moved on to OSV’s where i have been every since. While working on ship assist tugs I developed a love of ships as well as tugs and I have always wanted to work on ships or ATB’s weather its at sea or on the Great Lakes. Fast forward years later and needless to say i have yet to leave the oilfield. So i decided to join gcaptain in hopes to get some advice. My plan is that maybe my C/E limited could get me a spot a QMED on a ship and maybe gain enough experience while running as QMED that i can eventually find a spot as engineer. I know it sounds crazy giving up a 150k per year to basically start over again but i have been working at lowering my bills the last few years as part of my plan to be able to afford a pay cut that i would take in order to do this. I was thinking I can apply to sit for 1st A/E and study but in the mean time work as QMED for experience. Can some of you guys and gals tell me how to get my foot in the door on the great lakes or any ship? Ive looked into MSC and im not so sure about that but its a option. Drill ships are a option as well. Thank you to anyone who replies .

Does your MMC include QMED? Since 2013 in order to sail as a QMED you need to have that endorsement in your MMC. Cee CG-MMC Policy Letter 4-18. If you have CE-Ltd you should not need any exams, but you will need to apply to have it added,

My DDE unlimited has QMED under the capacity section but when i got C/E limited it doesn’t say QMED under the capacity section. Just C/E limited. Thank you, i will ask USCG about that.