Automated testing on actual mobile devices (Android and iOS) would be useful to make sure we don't break anything working on them.
Describe the solution you'd like
BrowserStack is free for OSS (not sure what the limitations are though), and lets you test against real mobile devices. Bevy is using it to try and catch regressions that would break rendering on mobile devices.
Describe alternatives you've considered
I haven't looked into any competitors.