I have recently verified that the ISY994i-ZW+ is not Z-Wave Certified, despite being marketed as Z-Wave Certified by Universal Devices. The earlier model was Z-Wave Certified (not plus) but no longer sold.
I learned the hard way. I had to return an ISY994i-ZW+ for refund after adding numerous nodes and experiencing massive failures. I had to factory reset 80 nodes, then I installed a HomeSeer Zee Controller and it worked well during inclusion and setting up events. One thing that is nice is that you can push the dimmer parameters to the Inovelli Devices via the GUI; you don’t have to stand at the dimmer to program the parameters.
I am now curious and will buy a Hubitat just to compare the Z-Wave integration to Homeseer. I’ve never been a big fan of Homeseer, it’s kind of kludgy. The Homeseer help files are incomplete IMO, but it helped us solve a problem and get the Z-Wave network up and running pretty fast.