Upgrade them to the latest version from here.
But slow is relative, copy, scan etc should load within a second. But out of sleep ours all take nearly 2 seconds to load whatever icon we select, everything after is about 600ms, once in an option like email or copy, there is a 400-500 ms lag.
Now comparing that to a flagship phone, horribly slow. Compare it to a midrange phone, not terrible, compare it to Konica/Minolta, Canon Imagerunner etc, pretty much on par in my experience.
Speed of remote apps will be drastically slower though, troubleshooting that requires Wireshark traces, once those are obtained, call Xerox, get to 2nd level and ask them to get the engineers to look at the trace and see if they can do anything.
It can't hurt to just disable McAfee and see if that resolves any of the speed issues ala CWIS > Properties > Security > McAfee Embedded Control
If it takes too long to print jobs from the LAN, that would likely be DNS, in short, the printer does a DNS lookup on all devices that send it a job, if it isn't on a Domain, or at least properly registered in DNS, this can cause an issue where it fails, but it will keep trying until the DNS timeout occurs, so make sure it is set to the minimum 1 second as opposed to 5-15 that Xerox suggests for the Fuji/Xerox controllers like the WC560 (Note, mine is not registered per the red text, so not setting this to 1 for me does indeed cause very slow FPO)
Normally I would suggest an altboot with no data backup and no clone be done, but since you have 3 with the same behaviour it cannot be corruption unless of course a clone file was used to configure all 3, which would imply the clone came from another device entirely (the 072.xxx.xxx.09100 firmware would have allowed that sadly). Only in that case do I think the Altboot, no data backup no clone method would work.