Don't want to be harsh or question your capabilities, but I know some authors around there who've had hard time with their coder, because they absolutely not had the capabilities they claimed to have. So, if you could make public some demos, it will probably help you find an author/team ready to take you. Obviously not a compiled and working thing, but some pieces of code you wrote yourself. You know, just for them to verify that they'll not have to pass half their time to debug your code or explain you in detail what you need to do.
Seems fair. Like most devs, I would like to do not identify myself and my previous codes belongs to contractors or clients. My hobbyist codes are all in my Github page an can be used to identify me.
Thats why I want to build a portifolio, so I can show something. I will try to find codes that I still have and never published, to show in a Github page.
People are are always in need of good coders, i think perhaps stating what languages and software experience you have in detail would help though, UE4 isn't that commonly used in adult gaming to my knowledge, though it is one of the more powerful engines that the public can easily get at.
Hope you find a project to contribute to, good luck
Truth, since UE4's learning curve is not so fast as Ren'Py for exemple, it's not common using it in any kind of indy project. But if the artist works with Photoshop, Daz, Poser, etc., I don't think it would be a problem. UE is very powerfull, and has tools, like engine programming and UI editing, that would really make everthing easier to develop.
I can program in other languages, primarilly web (Javascript, PHP, etc.) and Java, Python and C++, but I can attest that if you know how to use a more powerfull game engine (UE4, Unity, CryEngine, etc.) you should go with it, because in the end, its faster and better.