I've found what the problem is. There is no explicit error on Joplin side, but the UI is freezing during note indexing. I'll post the info as a separate ticket on the github project's page.
I've successfully compile and run the app from the source on the android phone.
Problem:
- i've circa 1500 notes (history from the evernote) and more than 5000 (didn't count) attachments (images etc.)
- when sync'ing on the mobile the device synchronizes the data for the first time
- on the next sync application is performing indexing. The indexing in my case take a very long time and during this phase the interface is freezed (ui lock). On Samsung S20FE (Snapdragon 865) the indexing (notes + attachments) take a very long time. I have successfully synchronize only notes and attachments leave on the manual download. The indexing takes some time (didn't count but leave phone always on with priority boost on joplin app) and it finished successfully.
- next sync is much faster and only a small fraction of tile (ca 0,5-1 sec) the interface is freezed during indexing