I've been through the same dilemma and I found out the key to the wider space. Use English to practice and follow what you LOVE and are PASSIONATE about. That way, you get out of the narrow boring space of just learning for IELTS and you stat enjoying the journey.
IELTS subjects remind me of the boring school subjects that I had to write about or even draw in the art class like writing about the national day, drawing mother's day. It feels like "What the heck are you talking about?", I'm not even interested or motivated.". If you lock up yourself inside IELTS only, the odds are you will feel boring like hell. Instead, practice on what you love, and that will definitely help.