I'd recommend trying to figure out why doing what you were trying to do wasn't working, instead of just going "screw it" and causing problems. Merge might be the wrong option, there might be a different option to do what you're trying to do.

OSM is collaborative, which means people are going to have issues if you do the wrong thing, and will call you out on it if you're making invalid/incorrect edits or not following the general expectations of mappers. People also have less tolerance for those editing for golf simulators because of constant vandalism as a result of it, which includes other changes you've made like setting a peninsula to water.