Six Switch Circuit Possible?

I have been using the Ultra Pro switches to automate lighting. Everything is set up through Google Home. I have a couple of three-way circuits that are working perfectly, and one four-way as well. Trying to decide if I can do my floodlights. There are a total of six switches that can turn on/off the floodlights.

The Ultra Pro literature says that these switches "Can be used with standard 3-way switches for ON/OFF operation or up to 4 UltraPro, Enbrighten and JascoPro Series add-on switches to maintain full functions of the smart device from every location."

So, the way I read it, the maximum number of this type of switch I can use is one main switch and "up to 4 UltraPro, Enbrighten and JascoPro Series add-on switches", giving me a total of 5 switches.

Is the Ultra Pro limit of four add-on switches surmountable, or do I need to look for other options? If I do need to look for other options, are there any suggestions?