By comparing the numbers of elements in the 'sync status' panels on the Linux and on the faulty Android, I see there is just ONE element more in Android, which (IMHO) generates the sync status error.
I installed the Note Info plugin, I see I can do a lot with it including deleting a given note, but as I don't know how to select the troublesome unsynced item I just cannot use the Note Info to eliminate it....
Then I tried the approach desrcibed by @personalizedrefriger in post #2 above : I got the log text associated to the error, below, but I don't know how to kill the related item...:
05-08T18:04:26: "DecryptionWorker: error for: 1f7cb89cb721480ebe5040ac8d99a18c (notes)", "TypeError: Cannot read property 'id' of null
TypeError: Cannot read property 'id' of null
at ?anon_0_ (address at index.android.bundle:1:1699466)
at next (native)
at fulfilled (address at index.android.bundle:1:1685034)
at tryCallOne (/root/react-native/ReactAndroid/hermes-engine/.cxx/MinSizeRel/5p1x2e66/arm64-v8a/lib/InternalBytecode/InternalBytecode.js:53:16)
at anonymous (/root/react-native/ReactAndroid/hermes-engine/.cxx/MinSizeRel/5p1x2e66/arm64-v8a/lib/InternalBytecode/InternalBytecode.js:139:27)
at apply (native)
at anonymous (address at index.android.bundle:1:249413)
at _callTimer (address at index.android.bundle:1:248362)
at _callReactNativeMicrotasksPass (address at index.android.bundle:1:248526)
at callReactNativeMicrotasks (address at index.android.bundle:1:250501)
at __callReactNativeMicrotasks (address at index.android.bundle:1:152257)
at anonymous (address at index.android.bundle:1:151350)
at __guard (address at index.android.bundle:1:152098)
at flushedQueue (address at index.android.bundle:1:151261)
at invokeCallbackAndReturnFlushedQueue (address at index.android.bundle:1:151204)", "{"user_data":"","master_key_id":"","conflict_original_id":"","share_id":"","is_shared":0,"encryption_applied":1,"user_updated_time":1689677985325,"application_data":"","source_application":"net.cozic.joplin-mobile","source":"joplin","is_todo":0,"markup_language":0,"order":0,"latitude":"0.00000000","encryption_cipher_text":"JED0100002207beffaaa79985462fab6c20bd2248a5d500080c{\"iv\":\"xcndKt4fi1OwmUqmqzTbCQ==\",\"v\":1,\"iter\":101,\"ks\":256,\"ts\":64,\"mode\":\"ccm\",\"adata\":\"\",\"cipher\":\"aes\",\"salt\":\"ujZYJ8PSu94=\",\"ct\":\"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\"}","longitude":"0.00000000","deleted_time":0,"is_conflict":0,"todo_completed":0,"altitude":"0.0000","parent_id":"ff1c6c63dc474e43bb39ca69ea26141b","title":"","source_url":"","updated_time":1690208140887,"id":"1f7cb89cb721480ebe5040ac8d99a18c","todo_due":0,"author":"","user_created_time":1689677985231,"body":"","created_time":1689677985231,"type_":1}"