Apple Watch Ultra underestimating distance by 5%

I’ve recently gotten into running after having an Apple Watch Ultra for 18 months. Now it’s

started annoying me as I run with my friends with Garmins and other watches that all give them 5% more distance over the same circuit. Strava and their watches say this circuit round KLCC park is 1.36km

my Apple Watch Ultra believes it’s 1.25km and 8 laps is exactly 10k which is really more like 10.5 on all my friends gadgets.

i recently traded it in for an Apple Watch Ultra 2 hoping this would fix the issue and for the first lap it gave me the right distance 1.35km, I was so happy until the second lap where it seems to have recalibrated itself to be wrong and the same as the old watch.

Is my only solution to get the correct distance and therefore pace to buy a Garmin? This would seem such a shame.

Please help.