Background: So I am a professional in the advertising industry with a university degree behind me. I don't really want to forgo my career to learn Japanese, but after my last trip there, I would like would like to hone my skill so I could feel comfortable finding employment in Japan within the next 2 years.
I have done random little courses here and there, and already have a basic understanding of the language to a degree where I can talk about some basic things or ask simple questions if someone is willing to talk slower with me.
Root Question: What are some viable/intuitive methods for a person to learn Japanese when flexibility is important? I am willing to spend money, but I want it to be a good system to help me learn intuitively.