so they are on the wifi using wifi or on wifi with an ethernet cable to your router?
I having trouble 100% determining your configuration with your chosen description

if they are connected with "wifi" to your router try using an ethernet cable that should fix issues.
my printers are available on wifi but by connecting to a router with cable.. much more reliable.
I had issues with waking from sleep on wifi(not hardwired) at one site.
Still 1/10 the issues I had with canon and HPs (at least home models)