In microG 0.2.27 was a fix that made location work and positive reports came in, something must’ve changed - Car sharing app Miles uses wrong location - #24 by vossi
A logcat will give you better clues than a package capture why the app is crashing (or voluntary exiting). There are on-device apps, but if you’re familiar with adb it’s a bit easier. Just mark the last line by mouse double click before the interaction that will make it crash, and afterwards ctrl+shift+mouseclick to mark the last → localised crash log.
(you can try to book Miles cars through FreeNow as a fallback)