My workplace plans to install 2 ISPs (300mbps and 100mbps) for 2 buildings. so each building does not interfere with the internet speed of other buildings but can still communicate (building 1's PC can ping building 2's PC for example)

My Mikrotik has 12 ports (cc1016)
each building has its own switch

Now the scheme I have in my head, 2 ports are enough for one building
for example ports 1 and 2, port 1 is for requesting IP from the ISP router, 2 are to the switch, so the switch can be connected to an AP or computer

then everything is repeated so you need 8 ports (4 isp 4 switches).
then port 2 routes to port 1, port 4 routes to port 3, etc

Is the scheme correct?