I'm a little hesitant to say the following, since I don't collect metrics, and thus it's maybe a bit unfair on Mullvad, but: sometimes the Belgian Mullvad locations can be a bit slow. I've had that feeling from time to time, and on a few occasions when switching to their Netherlands locations I get better speed. Right now for instance I get close to full theoretical speed as promised by my ISP while going through Mullvad Netherlands, and only a quarter of that speed through the Belgian locations.

One of the most used podcast apps on Android has to be Pocket Casts, and they support removing silence : https://support.pocketcasts.com/article/audio-effects/

That's too bad: on my OnePlus 6, the latencies for your app are great. It's the first time I'm drumming in an Android app, and am not bothered by latency. Thank you for having the source on Github, I'll amuse myself this weekend checking the code.