Note10 gets hot using Type-C earphones and fast charger.

As the number of smartphones with USB Type-C earphones increase, you are using dual adapter that allow device to use USB Type-C earphones and a fast charger at the same time. However, some dual adapters may cause overheating or prevent sound from the earphones when the charger and the earphones are used at the same time. Dual adapters that do not meet the USB standard are especially likely to cause those defects, so it is recommended that you use those adapters carefully.

• Overheating problems or damage to the earphones may occur when a charger and earphones are connected at the same time using a dual adapter.
• Earphones may not work when charging with a dual adapter.

Samsung recommends to use Samsung-approved accessories. Using unapproved accessories may cause the performance problems and malfunctions that are not covered by the warranty.
 

And please check the performance and safety of products from other manufacturers before purchasing or using them.
 

As some USB Type-C earphones and adapters may not be compatible with device and some features may not work properly, make sure they are compatible with the device before purchase as well.