Sideface:

 

No one device will do all this.

 

First, forget the printer - it uses way too much power, even for a high end UPS.

 

I have a similar setup to yours in my home office.

 

I use 4 UPS units :
1 x APC 1500VA unit for two desktops - will run for 30 minutes plus
2 x APC 700VA - one for each NAS, to allow a graceful shutdown.
1 x Constant Vigil Sentry Lite unit for the ONT and router - will run for 6 hours

This

I'm fairly sure my UPS even says either in the documentation or on the back where the power sockets are "Don't plug in a printer". I think this is because a printer uses relatively a lot of current when starting up.
Anyway, if the power is off, what's so urgent to print something?
If you need to keep running continuously through a prolonged power outage, you need a generator as well as UPSes - this is a whole new world of fianancial pain, b.t.w.

Make sure that the UPS(es) for the NAS devices will keep them going longer than the PCs' UPS will keep the desktops going, the PCs will be useless if the NAS devices have shut down already

My setup is:
1 x Dynamix 1600VA powering a main & an occasional-use PC and a POE switch which powers a WAP
1 x Constant Vigil Sentry Integrated unit for the ONT and router