To keep the full bandwidth of moca 2.5, you have to install as point to point, e.g. a moca modem on each floor and one for each floor in the central location. That way you don't share the total 2.5 Gb/s bandwidth with other nodes on a combined coax installation.Simplify your life, this isn't a decision you have to make immediately. Drop a MoCA on each floor coupled to a mesh forming a 2gb backhaul to your main router. You'd have an AP on every floor. Even a little RP-AX58 mesh node could suffice backhauled to the main through MoCA.
The ethernet port from each moca modem in the central location is connected to a switch, either on the router or a separate switch.
for most home use cases, it doesn't usually matter if the coax is shared among multiple moca nodes as the individual client bandwidth requirement is low.