If you mean, z wave range extenders, you don’t need them. They were useful back in generation three, but we’re now in generation five, so any mains powered device like a light switch or a smart plug will do just as well at repeating and give you dual use for better value.
If you mean, Wi-Fi range extenders, if you’ve been using the ET – WV 520 as your Wi-Fi router, then you have to get a new Wi-Fi router. If you want Wi-Fi mesh, there are a number of good choices these days, almost all of which are better than the old Samsung models Because the Samsung devices required an active Internet connection in order to run, and that should not be necessary for a Wi-Fi router. (Wi-Fi and Internet are two different things.)
I don’t know if the new hub transfer utility will work from a ET – WV 520 or not. You may have to check with support on that one.
If it doesn’t, then you just have to go one device at a time and exclude from the old hub and then include to the new one. The exact process for each device can vary, so you’ll need to dig up the user manuals online. It’s tedious, but doable.
If you do have to move them individually to the new hub, follow the suggestions in post 11 of the following thread. (I will link directly to post 11) and the process should go pretty smoothly. 