Help getting 5 static IP's into layer 3 switch and distributed

Upgrading a school that currently has 15+ year old Dell Powerconnect switches and have a question about how some static IP's are pulled in.

Building gets 5 static IP's over fiber. The ONT currently appears to plug into the current Dell switch. From there, it's sent to various other parts of the building using VLANs where other systems are plugged in (like HVAC gets one IP, VOIP system, and then another tenant gets another IP and has their own router and switches.) They want the static IP's to be used so the networks are separated and if the HVAC system or VOIP system were breached, hacked, etc. it wouldn't contaminate their main data network. They also don't want the other tenant anyone where on their network. They give the tenant a port on the far side of the building IDF so they can feed and manage their own network.

Is this easy to do using Unifi Switch Pro 48 POE's? (It's Layer 3)

I've setup dozens of networks where one IP is brought into a router/firewall like the USG Pro 4 or UDMP, then distributed to a switch. I understand the basics of layer 3 switches but have not built up a network this the one I'm describing feeding multiple tenants with different IP's. Any guidance to get my head around how to route raw internet WAN IP's through the switch would be helpful. Thank you for guidance.