pCloud, Cloud Sync not working properly

I’m still trying to find a solution to sync pCloud with DS1821+ following my previous post.

All files that were on pCloud I copied to the nas from my PC. About 1.5tb. In the end I did connect the nas using Synology Cloud Sync with WebDAV, Bidirectionally, and everything appeared to be in sync.

When I add files to the nas, they are immediately uploaded to pCloud. No problem.
• However it’s not the same for downloading new files from pCloud.
• I setup a new test folder on pCloud around 2.2gb. The nas has only downloaded 370mb. Over the week, no further files are downloaded.
• The status of cloud sync is nearly always “connecting” If I pause sync, and reconnect, it says up to date. There are still files missing.
• If I delete files from pCloud in my test folder, they get deleted from all computers connected with pCloud, but not from the nas. If I do a hard restart of the nas, quite often the file gets deleted.

The way things are, I don’t trust the nas to be accurate copy.

Are there any settings I can check, or any other way to connect the two for a novice.