You’re looking for a 48 port router, which really isn’t a thing. My suggestion is get a 48 port switch, assign each of your machines to their own VLAN, and then use an upstream router to handle all your NAT needs.
Ubiquiti does make some 48 port switches, but I would advise towards more ‘industry ready’ hardware (Cisco, Arista, Aruba, etc.) or use whatever your IT department is comfortable with. If your budget only allows for Ubiquiti then so be it, just know that it may end up being the weak link sometime down the road.