Based on the Scheduling Push Upgrades and the Push a Package Upgrade documentation, while Salesforce UI to schedule push upgrades is available for first generation packages (1GP), for second generation packages (2GP) there is presently only a set of APIs.
Before I go off and create my own app to schedule/monitor 2GP push upgrades (looks like multiple days fo work to do):
Any expectation that Salesforce will build UI for this soon?
Anyone about to release some open source for this or post a free app on https://appexchange.salesforce.com/?
Does a commercial product have this capability already?
Or if you are seriously interested in sharing the work of building such an app comment here and we can figure out a way of getting in touch.