unxrules wrote:
another family member's phone have both been making accidental outbound calls even when we don't have the actual phone app itself open.
You need to look for it in the App Store.
In Apple Support Community, the focus is typically on helping users and providing solutions rather than promoting or advertising specific apps. If I suggest apps from the App Store as a community member, it's possible that the community moderators might consider it as a promotion or advertising.
They have guidelines in place to prevent excessive promotion, spam, or conflicts of interest. These guidelines are designed to ensure the community remains a helpful and unbiased space for users to seek assistance.

To curb automatic dialing...
The slightest touch on the edge of the screen while holding the iPhone in your palm may trigger this.
Go to Settings > Accessibility > Touch, then tap Haptic Touch or 3D & Haptic Touch. Choose the touch duration—Fast or Slow. On an iPhone with 3D Touch, you can choose the pressure needed—Light, Medium, or Firm.
Adjust how iPhone responds to your touch - Apple Support (IN)

There are two steps to do that.
- Check your iPhone display before you put it aside or in the pocket. iPhone display will turn off only after your Auto-Lock time settings.
- If the display is ON, lock the screen using the side button and check your iPhone display before you put it in the pocket
Sleep
On iPhone 6 and later, and on iPhone SE (2nd generation) and later, press the side button to wake your iPhone or put it to sleep. Press the top button on the iPhone SE (1st generation) and earlier.
Learn about the buttons and switches on your iPhone.