Device Changer

Device Changer is an LSPosed module. It is not a cloud device farm and not an emulator. You install it on a rooted Android 12+ device, pick a saved profile, and the app under test sees that profile — model, build signals, and identifiers — instead of the physical handset.

That is the product difference: one device, many documented environments, so a bug report can name the profile instead of “works on my phone”.