Sigi, fyi automatic synch works great for me on both Windows and Android. Only exception: if my phone battery is low then Battery Saver kicks in and autosynch stops. When I get home, I plug the phone in, and without any further intervention from me, Battery Saver drops and autosynch runs. By the time I get to MLO on windows, it is up to date.
On the other hand, you have experienced crashes and continued. The first crash probably damaged your database, causing the subsequent crashes which make it worse. This is not okay. Crashes are not normal. People are not supposed to "learn to live with" crashes. People are not supposed to ignore the damage that crashes are doing to their database.
On the device that's crashing, go to settings>troubleshooting and enable logging.
Include a message telling what was going on and copy in any error message.
Hope this helps
-Dwight