Removing DC wander in the offset of a DC-biased audio signal
This isn't DC wander, it's just AC coupling of a signal which has DC content. There are three common solutions to this problem :

(1) remove the AC coupling. This may not be possible; the Android may incorporate its own AC coupling. You can test this by looking ahead of the coupling cap C1. Unless your scope traces are inverted, if you see DC when idle then you can do this.

Then you need to replace the DC offset somehow... easiest way is to connect the bottom of R2 to the audio jack (LHS of C1) instead of to ground, removing C1 altogether.

Your last photo shows this option won't work; your input signal is also AC coupled, with a longer time constant. So, moving on:

2) A "DC restorer" (also known as a diode clamp in the analog TV days) You need a reference voltage, at 1.65V minus a diode drop, and a diode from "Audio" to this reference. As the signal drifts positive, the diode conducts, clamping it to prevent the drift. The negative peaks remain close to 0V. Details left as an exercise...

3) The way communications links are designed : eliminate the DC component of the signal so you can AC couple it without problem. There are any number of ways to do this - wiki Manchester coding for one, 8B10B code for another. The basic idea is that both 0 and 1 are represented by square waves (say, of different period) and the signal doesn't ever rest at either rail for any length of time. I'll go into more details of a simple scheme if you wish.

A benefit of a DC-free signal and AC coupling is that the comparator is set to a local "0V" point (like your supply/2) and works regardless of the signal amplitude (cable length, Android volume setting)