Apple Watch timer unreliable

I can’t rely on the timer on my Apple Watch 5. 99% of the time it stops before the time is up, I’m guessing because the stop button gets touched accidentally. I’ve tried many things to prevent the app from displaying unintentionally, including opening another app so it should display if the screen wakes as I walk around. If the timer is going, however, it seems to supersede any other apps I’ve used since the countdown started. The only thing that helps is turning on the water lock feature, but that gets inconvenient if I need to use my watch multiple times while the timer is going. Any fixes I may have overlooked?