You may consider using a second, inexpensive Android phone dedicated solely to operating the Onewheel app in order to maintain operational integrity on your main device.

Acquire a budget Android phone. This device doesn't need to be high-end; its primary function will be to run the Onewheel app. If you want to splurge a bit, you could find one that supports GrapheneOS and install that.

Your secondary device will need internet access to download the app and receive updates. To avoid using a separate data plan or compromising the privacy of your main device, you can tether. Don't use it otherwise.