Throughout the question, you provide examples of programs you've tried and some specific concerns you have about your situation. That's great! Unfortunately, recommendations for off-site resources (including programs) are off-topic here, as noted by the closure reason.
It is possible to ask questions that will probably require third-party software, but here, it looks like the question was closed because of the title ("Real-Time Sync Utility") and the opening sentence:
I'm looking for something to synchronize my Computers with a NAS in the local network.
It's easy to forget to update the title after changing the body - I've missed it myself a couple times! - but people usually use the title to assess what the question is primarily about. Modifying the title to describe your situation would help.
You did adjust the closing sentence, and that's good. A bit more wordsmithing in the rest of the question might be able to make it clear that you're not necessarily looking for a software recommendation. In fact, your question does have one reopen vote pending at the moment.
Though if you are looking for a software recommendation, we have a sister site for that: Software Recommendations. Thanks to all the information you included, you have most of an SR.SE question already.