Switch and balancing

Hello.

I have ISP on port13 and setting route 0.0.0.0 to gateway ie. 1.1.1.1
I have my local subnet 192.168.1.0/24 on port1 NATed to public IP 1.1.1.2.

Now, I have second gateway ie 2.2.2.2 accessible on port13 too.
I want use port12 as switch to port13
(I want do accessible gateway 2.2.2.2 for whatever on port12 without routing)

PORT 1: Private LAN
PORT 12: Switch port of PORT 13
PORT 13: Gateway 1.1.1.1 and Gateway 2.2.2.2

I searched something but I’m not sure how can I right do it.

Finally, is it possible do balancing between routed port and switched port?
I want balanced access of internet 50/50 for port1 and port12.

Thank you for help.