Hey! I'll take you up on that — happy to test Burp Cubes for the full 14 days. Quick context: I actually built a small tool called PeerPlay specifically for this kind of swap (add your app, testers commit to real daily sessions, you test theirs back). Not trying to sell you on it, just mentioning it in case tracking a 1-for-1 manually gets annoying once you're juggling a few testers. Either way, send me the opt-in link and I'm in.
https://play.google.com/store/apps/details?id=com.testerhub.app