At version 2.9.3 (and Enterprise 10.8.1 in case that matters), ArcGIS Pro only allows me to overwrite a web tool owned by me--when exploring my Portal for tools to overwrite, the only node I'm given is "My Content". This isn't feasible in my org since we hand off all of our public-facing items to a generic built-in account whose primary purpose is to unify all supported content under one identity. Besides that, there are three of us that might have to support any one of our several web tools. The only workaround I can think of is for an admin temporarily to change the tool's ownership while republishing, but this seems more trouble than necessary (especially when Enterprise's default behavior requires admin rights to publish a tool in the first place, which seems strange to me, but that's a separate idea).
