Hello zippycom,
Thanks for posting on Apple Support Communities. It seems that your iPhone XR battery is draining quickly. You mentioned that this issue was also happening on your previous phone, the iPhone 6s Plus.
When you first set up your iPhone XR did you restore from a previous backup or did you set it up as new? If the issue you are experiencing is the same, it's possible that there is a software issue. If the phone was restored from a backup the existing software issue would then be transferred to the new phone. At this point we suggest you restore your phone to factory settings and set it up as new. Restore your iPhone, iPad, or iPod to factory settings.
If you didn't restore the iPhone XR from a previous backup, these articles may be helpful in optimizing your battery and maximizing performance:
Have a great day!