Apple Watch Series 5 Nike 40mm

I Bought the Apple Watch Series 5 Nike 40mm to improve my health and training for running marathons. It has worked fine but recently the AWs5 is reseting after my workouts. I use the app WorkOutDoors, I normaly run 10-15K and then walk 2 Km to cool down. My apple watch resets after finishing my workout. The same happens with the native running app. The AW resets and then gets into battery saving mode with less than 10% of battery despite the fact that when finishing the workout is saying between 88 and 80% left. When I arrive home, and I connect the device to the power charger the battery start charging from higher than 50% not 10%. I have lost most of my running data during the last 2 months, althouh sometimes workoutdoors app manage to save the data. I would like to use the apple watch for tracking hikes but its not reliable. I am running iOS 16.5 and WatchOS 9.5; my apple watch battery health is at 80%. How likely is that apple replace either the Apple watch battery or device? I dont have Apple care. thanks.