+1 for this approach. For a mobile app, I made Nix spawn an ephemeral Android emulator instance for generating up-to-date screenshots, requiring no prior setup and leaving no lingering data around after running. Setting it up wasn't that high-effort in my case either; coming up with the idea was the hard part, the Nix code was one-shot by your favorite LLM.

Granted manually updating the screenshots isn't the most laborious task in the world, but the "upload-apk + take-screenshot + transfer-back-to-PC + edit" process is usually barely annoying enough that you end up almost never doing it otherwise (similar to the OP's experience in the closing paragraph).