Just use Krux with Sparrow once... You can test drive with Krux app, without spending a single sat.
https://github.com/odudex/krux_binaries/tree/main/Android
It's simple and objective, big QR codes and touchscreen.
Later, for a few sats you can buy an Amigo(ready to use), just flash the firmware and have the same touch UX, on a dedicated device without OS and wifi/BLE.

Krux creator, Jeff, is around. He hasn't been working on Krux recently because he is busy with other personal priorities. I have no idea where he is from or where he lives. He dedicated some extra effort to add Vietnamese language on Krux, so maybe has an affinity or link with Vietnam.

Nice! While you wait you can test drive Krux with the app:
https://github.com/odudex/krux_binaries/tree/main/Android

You can also join Krux Telegram group to get help and more project news:
https://t.me/SC_Krux