It seems like this has been in the works for a long time?
From the post announcing the "New and Improved On Later" (emphasis added):
On Later is finally in the app! As usual, it's in the tvOS/iOS version first, but it will come to Android soon.
(As usual, new features are delivered to Apple clients first, with Android following up with parity at a later date. The delay is because the code must be ported over; the Apple and Android clients do not share a unified codebase.)
Feature was introduced Aug 2021.
Its reasonable for comunity to ask if there is a delay, technical hurdle, or abandon idea.
Its also reasonable for devs to remain silent and ignore us.
Yes it will be coming to Android. We don't have an ETA yet.
Thank you @tmm1 sometimes as a community we get impatient.