[Ultimatt]

Instead of finding your weakness and patching that up I would find what you are already strong at and take that to the next level. Then just present yourself as only that person. Craft your image to fit your skills not your skills to some image you wish to project. Unless you are highly competent and a really good self study you wont be able to pull off looking like a 10x Rockstar in blah if all you have is a coursera certificate and a really bad GitHub project. If you have 2 years experience and a highly functional app in something else then lean on that. You can always say you're looking for an opportunity to move field/role with a bit of evidence.