Microsoft will include the Edge WebView2 runtime with Microsoft 365 apps for enterprise version 2101 or later. This doesn’t mean they install Edge; it’s simply a software component to make it possible for Outlook desktop to run features developed for OWA. You can block the deployment if you like, but there’s really no good reason to do so.
Project Moca is a new Office 365 personal productivity app which doesn’t have a mobile app. It’s hard to be productive if you can’t be when mobile. Which is why To Do allows people to capture thoughts. A workaround of sorts is available through To Do tasks. Whether this is enough for you to switch to Moca is debatable.