Every now and then I will come across a question like this from a higher belt and it's not an easy one to address.
It's also one of the main reasons that instructors will focus strictly on the fundamentals in the beginning of your practice as those fundamentals will support you in learning new techniques and when you come across different challenges.
With the advent of YouTube alongside social media as a whole and the explosion of the instructional market. There's never been more available jiu jitsu knowledge than now.
However, with more knowledge can come this feeling of being overwhelmed or sometimes an overemphasis on getting better faster at the expense of learning those fundamental details.
In special cases like this I think its important to work backwards from the beginning and I know it won't be easy.
The first step I will have students take is to look at their guard basics such as how they retain their guard in different situations and passing attacks.
This is where a majority of the holes in a guard game appear.
Especially at a higher rank as you will need to be prepared for different guard passes, different styles, body types, age levels, size, etc that will take time to build.
The next thing I'm look at is how the student transitions from one guard to the next or into and out of their main guard.
This can also be a large sticking point since a lot of people tend to stick with the same guard but never evolve it. Which means that their training partners will often come up with counter measure against them
A lot of students will take this as them losing in training but for me this is where you need to start evolving your guard in response to what your training partners try to do to you.
For example if one training partner tries a different approach on me that works. By the next training with that partner I should have a counter to that technique ready when we roll.
This is a constant process and I can assure you that you will never reach a point where you will be fully satisfied with your game because there will always be something more to work on, to add, and to innovate upon.
The last thing I look at are the students attacks also knows as their submissions and sweeps.
These are your trusted weapons that you can rely on during your darkest moments like when your competing and your down on points with 30 seconds left on the clock.
Jiu Jitsu at the end of the day is a submission art form and your submissions will need to be finely tuned as you reach higher ranks.
I know this can all be a lot to take in but as with any big project don't go tackling everything all at once. Instead break it up in to many smaller sized projects that you can knock out.
Oh and do a lot of positional sparring!