Hi and welcome.
I don't do MMA but I have some ground fighting experience (Judo and some BJJ).
I've said this before, people tend to have a "natural" range. For some people it is punching, some kicking/striking with legs, for some people it's stand up grappling, for some folks it is ground work. For some people it is a combination of the above. The question for me is: Is it best to work on ranges you have trouble with, or is it best to maximize your potential by working on the range you feel most comfortable in and learn more quickly in? It depends on what you are looking for really!
To me your choices are either: Speak to your coach about how to improve your striking overall in MMA
Think about whether or not for the moment you'd be happier working on a range you enjoy more and feel more comfortable in. For instance you may enjoy ground grappling more. You might want to focus just on ground grappling for a time and nothing else. When you spar you might want to just do ground work sparring.
Someone once said that modern MMA is about 2 people with various skillsets. The victor will be the person who can implement their strategy best against another person. Their strategy will be determined in a major way by the range of combat the person excels at while also factoring in ways to negate the strengths of their opponent.
In other words, develop your strengths. If you find yourself lacking in striking but being a demon on the ground, figure out to get the fight to the ground as soon as you can. If you suck on the ground but love stand up, find ways of keeping the fight standing up.
"Let your food be your medicine, and your medicine be your food"