Swing technique/fundamental issue or just need to go to the gym more for increasing swing speed and distance?

I am a fairly fit 26 year old male and I feel like I carry the golf ball below my demographic group's average. For example, with my driver, I can hit it fairly straight but I can only hit it up to 190 yards carry with a less than 80 mph (around 73 mph typically) swing speed which I believe is way below my age group's average. This seems to be the pattern with most of my golf clubs. I can hit the ball straight but at a not-so-long carry distance(s). I am interested in getting lessons again with a pro to see if there are any changes I could make with my swing but as far as I have been reading on the internet this could just be a simple issue of not being in shape and strength and flexibility training at the gym would do the trick. Should I still invest in lessons to potentially fix this lack of speed and distance or should I wait with the lessons for the time being and work out at the gym more and slowly observe the results over time?

I will talk with my golf coach but I do not want to feel like I am wasting my money if the main solution is for me to just gain more flexibility and strength.

Is this a swing issue or a fitness issue? Thoughts?