What is the first class of router hardware past SOHO?

Hi,

I've really been struggling to understand how a network is designed beyond the classical home office network. The typical model seems to very commonly include an IPv4/IPv6 capable router, which always performs NAT on packets received from the LAN interface destined for the Internet, and IPv6 of some sort. Lately it seems routers are working very well with doing an IA_NA and IA_PD for a /64 residential size, single IPv6 prefix to distribute amongst the LAN segment.

I have had a few people ask me if I am segretating my network into multiple LAN segments, to disclude IOT devices from snooping on the laptops/NAS, or to more fully segregate guest traffic into its own area.

My networking skills rather stop fully at the residential. The model above must be roughly identical to a local branch router with a few distinct office departments - let's instead of calling it LAN/IOT/Guest, simply as Finance/Sales/Engineering. With this in mind, what type of gear do you folks typically go for? Is there a "tried and true" way to design a small network with multiple L2 networks?

I don't know much about Cisco IOS, but it seems reasonable that it can provide NAT across multiple networks onto a single WAN address, and we have seen plainly it supports IPv6 in almost all of its various permutations so far. I would guess that other vendors compete in this space with Cisco.

So my question is hopefully not technical, but vague enough for a small discussion - what is the next form of router after the SOHO class is inadequate, for the smallest of business networks?

Thanks for any insights! This is obviously a thing I want to (eventually) do but I'm happy to keep the conversation high level so that it is more interesting.