Hello dewey152,
Thank you for reaching out to Apple Support Communities.
Let's check your battery health since that may be a factor:
Look at your battery health
All rechargeable batteries are consumable components that become less effective as they chemically age. Over time, the rechargeable batteries in all iPhone and iPad models will diminish in their capacity and peak performance and will eventually need to be replaced. iOS can show show battery health and recommend if an iPhone battery needs to be replaced. Go to Settings > Battery and tap Battery Health. Battery Health is available only on iPhone.
Additional steps to try can be found here: If your iPhone or iPad is running slow
If the issue persists, can you provide a few more details? When did you first notice this? What is your exact iOS version? Also, does this happen with all calls or just certain calls?
Cheers!