Using classic Outlook for Windows in business environments
I am a big user of the To Do app myself, for keeping track of everything. We also use Planner for tasks within various departments, and these tasks show up in the To Do app, so it's not something I can simply stop using.
The "old" Outlook desktop client has the To Do app built in. So you can use this "version" of the To Do app which does open the items in Outlook.
A nice little trick is to right click the To Do app > Pop out app
Better than nothing, since, yes, it seems like MS wants to force us into the severely feature lacking "New" version of Outlook (read: OWA wrapped in a "desktop app").