A router usually can do all that but it also does a whole lot more, like NAT, DHCP, etc. Sometimes you need a just a switch that understands VLANs and link aggregation
It’s been a bit since I saw that last season of DS9, but Ezri and Worf were never in an actual relationship so there was nothing to “break up”. They had a few moments, but that Ezri was clearly confused and overwhelmed by their past