A Good repeater near the hub should fix that issue.
taking from the linked article above.
Z-Wave, or z-wave plus? What is your battery to line/mains power devices? Do you have any repeaters?
It sounds like your mesh needs more meshing not more hubs.
And trust me I am not debating the weak signal is Hubitat's weakness, I came from ST too, and my locks have never been the same, even with repeaters. It seems to me Hubitat is much more reliant on a good mesh than other systems. Even if you HAD a good mesh you may not now.
The only thing that stays the same, is nothing stays the same!
If I were you I would buy some repeaters and sell the extra hubs on ebay. Those things are gold right now 
