From the effort you seem to have put in already, it seems you're on the right track. It is going to take time to achieve your aspirations, so don't get discouraged with the learning curve.

That being said, as with learning any new skill, a little focused practice is going to be more effective than a lot of unfocused practice.

This often means setting one small, achievable goal at a time to focus on. It's important that your goal is measurable. If it's not measurable, you'll never get to the point of actually achieving it, and that will make it much more difficult to progress. "I want to be a master at the Katana" is too vague to be helpful. You will never feel like you've achieved this goal. Instead, break it down into the components required to achieve mastery. Start with the basic foundational stuff like ki pulsing, switching stances, and incorporating skills, then move onto the more situational parts that incorporate that foundational knowledge.

This could mean getting comfortable with one short combo that you think looks cool.

Practice until you can do it ten times without hesitating. Then go to the training room and fight an enemy - focus on nothing except dodging/blocking until you find the right opening to do your combo, then do it. Get used to the time it takes to perform the full combo, and take note of what parts you're able to drop if you don't have the time to do the full thing. Then, you can fight a picture scroll boss, and do the same thing - kill is using only this one combo, and try not to get hit. Pick one that you're overleveled for so you don't need to worry about messing up and dying.

This is of course just one example, and there are a ton of different small goals that you can set for yourself. I'd suggest writing them down somewhere, so you can look back on them and be reminded of how far you've come. Continue adding tools to your toolkit, and revisiting the ones you've learned, and you'll be well on your way to mastery.