Not sure how you are deleting apps accidentally while interacting during workouts since you would have to press the crown button, touch and keep your finger on the screen until the apps start to jiggle and then touch the x to delete an app. Are you somehow doing all of this while interacting with the screen during workouts?
I think the only way to use any form of the screen time option in settings on the watch is if it’s a watch that was setup with Family Setup and only the iPhone that was used to set it up can do it to set restrictions (if it is similar to the iPhone version you can put a restriction on deleting apps). If that’s not how your watch is setup then that’s not a route you would want to go. Otherwise there doesn’t appear to be a way to prevent doing the steps required to delete apps on the watch.