Bad battery condition could possibly be the reason but there are other reasons. You don't tell us when exactly it is overheating; under what conditions. A battery at 75% is well below the 80% recommended replacement level and could possibly not be charging properly at all with some of the energy being lost to heat.
Go to this web site for information about how to request battery service for your iPhone: iPhone Battery Replacement - Apple Support
If you think there is a problem with a device, have Apple inspect it. Go to this page to find your nearest Apple Authorized Service Provider (AASP) or Apple Authorized Distributor (AAD) --> Find Locations
How to make a Genius Bar appointment
1. Go to Genius Bar Reservation and Apple Support Options - Apple
2. Go to "Get hardware help".
3. Select your hardware and continue selecting options requiring replacing parts until you see "Bring in for Repair"
4. Sign in with your Apple ID
"Your iPhone might get slightly warmer while it charges." - from: How to use your MagSafe Battery Pack - Apple Support
iphone/important-safety-information-iph301fc905/ios
Post by contributor Lawrence Finch explaining the basic physics. iPhone 15 Pro heating up with protective … - Apple Community
Section about "Prolonged heat exposure" in this support article --> Official Apple Support