For any amount of reasonable distinction of "servers" and "routers", you should never need a FIB install on a server. There are good reasons to keep these functions separate (most prominently, address ownership/binding issues with services that are frequently not designed to deal with multiple interfaces/route choices.)
NB: this is not about physical devices. VMs/containers on your host are frequently "servers" while the hypervisor is a "router".
For any amount of reasonable distinction of "servers" and "routers", you should never need a FIB install on a server. There are good reasons to keep these functions separate (most prominently, address ownership/binding issues with services that are frequently not designed to deal with multiple interfaces/route choices.)
NB: this is not about physical devices. VMs/containers on your host are frequently "servers" while the hypervisor is a "router".