[lallysingh]

So what you're missing is the 'drilling-in' you get from a CS program. Don't worry! You can do it to yourself in much less time. The rest sounds like consequences of that as well.

First, start a memorization program. This means Anki, really. Start putting in the basic OOP concepts you've forgotten that you feel you should know. Then put in more as you learn it.

Second, start reading up books on interview questions and (a) practicing them and (b) shoving facts to memorize (complexity of algorithms, basic implementation notes for common data structures) into anki.

Third, you need a project that stretches your skillset and lets you work deeply with areas that you need development on. That's either a low-priority side project at work or something at home.

What you're describing is exactly what's normal for engineers I've met who didn't get a formal degree. Nothing that can't be fixed with a bit of studying and practice. Honestly.

If this all fails, you can always play MIT open courseware at 1.5x.