Fenix 7X Tracking Issues, Pace & Distance Inaccurate

Hi everyone,

I'm having an issue with my Fenix 7X. I've synced Garmin Connect with Strava, and after each run, my activities upload to Strava without any problems.

However, I've noticed that my Garmin seems to be underreporting my pace. After a few tests, including today's run, I found a significant discrepancy. My Garmin Fenix 7X recorded 9.35 km with an average pace of 6:19/km, while Strava (recorded simultaneously on my iPhone) showed 11.68 km with an average pace of 5:03/km. That's a huge difference.

I'm struggling to understand which device is tracking my distance and pace more accurately, the watch or my phone. I've already gone through some insights shared in this forum, adjusted my settings, and enabled All + Multi + Band satellite tracking, but the issue persists.

Interestingly, when I use my watch for swimming, it tracks everything perfectly. Also, I use Garmin HRM PRO PLUS, can I use advantage of it so my distance would be tracked more accurately and represented on my garmin watch screen whilst running? 

Does anyone have any suggestions on how to get my Fenix 7X to track pace and distance more accurately?

Thanks a lot!