Apple Watch 6

I just got the Apple Watch 6. I’ve only worn Garmin fitness watches previously, so maybe I am missing something or am not operating the watch correctly. When I select an activity it counts you down from “ready” in 3 seconds and starts. Is there a way to change this to a manual start? When you stop a workout out you have to slide “back” one screen to press end. Is there a way to set the “end” or stop key on the main watch screen? These two items make an athlete using this watch extremely unfriendly.