"...Just purchased Sigma 135mm f2. I did not like the challenge the lens gave me following the ball..."
Mom, photographic excellence is decidedly not a consumer commodity... As many vendors of photographic kit would like you to believe... In fact they spend the lion's share of their profits on propaganda espousing the aforementioned myth... As do many hobbyist here on UHH who have fallen under it's sway...
The likely reason you find your 18-55mm kit lens more comfortable to use and generates better results is you have become one with that very user friendly and forgiving optic...
Enter "Stage Left" the Sigma 135mm f2... Guess what, this is Pro-Level glass... and demands far more expertise and photographic savvy than the the 18-55mm kit lens. You are now under the delusion that it is the tool and not the user that is at fault... Mom, you might be far better served coming up the curve on the Sigma 135mm f2... But I totally realize you don't want to hear that...
Bottom Line? Shooting Sports demands professional level of compliance in order to compete in the genre... This only comes with blood, sweat and tears... You are blessed by having a family member to document on their exciting journey... A very compelling reason to drive your passion here... Seek out YouTube videos on how to shoot indoor sports effectively...
Also there are UHH members who shoot sports commercially...
Please get off the Main Photographic Discussion Forum (which is overrun with naive hobbyist who only espouse camera vendor myths and pontificate on how 'savvy" they are).
Instead I strongly recommend you subscribe to the Sports Photography Forum and diligently study the post of actual commercial shooters.
https://www.uglyhedgehog.com/s-103-1.htmlI would also recommend you remain silent until you assimilated enough knowledge to make intelligent queries.
They totally understands what it takes and try to provide experienced guidance.
Mom, I'm only the messenger here... so if I've offended that's fine... just ignore and continue to bask in the warm glow of believing you can purchase excellence in Sports Photography, you are in good company for same in the Main Photographic Discussion Forum.
All the best on your epic photographic journey mom...
And please stay safe... Always wear a mask in public and practice social distancing...
Acute Respiratory Failure is a horrific way to die...