Hello rosana115,
Thank you for posting in the Apple Support Communities. I understand that audio speed and volume unexpectedly change in multiple apps when using wired or wireless headphones, and I'd like to assist you.
For this concern, I recommend removing the case and screen protector (if used), then testing the audio again with and without headphones. Also, try using these apps in multiple environments to rule out humidity, static, or interference: Resolve Wi-Fi and Bluetooth issues caused by wireless interference
Next, I suggest taking steps 1-3 here: If an app unexpectedly quits, stops responding, or won’t open. Forcing the app to close, restarting your device, and checking for updates may help.
From there, I recommend restoring your iPhone to factory settings using a computer. Please be sure you have a backup of your data to a computer or to iCloud before completing this step. This support article can help: Restore your iPhone, iPad, or iPod to factory settings. Once it's restored with none of your personal data on the device, test the issue.
If the issue persists, I suggest having a look over this Repair and Exchange Program, which applies to iPhone X devices: iPhone X Display Module Replacement Program for Touch Issues
I hope this information is useful. Kind regards.
