I’m going to buy QNAP TS-251B-8G and I need advice if there will be possible to run Netflix somehow? I know there is possible to use chrome, and open netflix page, but I don’t know if this hardware will be enough efficient to play movie on it?
Yes, you can download Netflix for Qnap here https://www.qnapclub.eu/en/qpkg/661 . This will be a wrapper version, but you can still use it.
You can also install it on a KODI if you have a HDMI port: https://www.youtube.com/watch?v=dyqSdYBo1mg
You can also get a QNAP TAS-168 or TAS-268 which features dual OS (Android and Qnap). This will allow you to install Netflix as an app just like on the phone.