How to remove double nat in local network?

Question

Computer networks

My local network is built like this:
1. Modem E5573Bs-320 on firmware 21.316.03.00.143, ip - 192.168.8.1, the same ip acts as a gateway for the Internet of the next router.
2.Beeline smart box turbo+ router, on Padavan 3.4.3.9-099_88a26f9 firmware, ip address of the interface for the modem is 192.168.8.100, local ip is 10.0.0.1, this ip serves as a gateway to the Internet for the next one.
3.Pfsense 2.5.2-RELEASE, this is already the main gateway in the local network, it also has Firewall, vlans, and so on.
4. Well, if it plays a role, the cisco sg200-18 switch.
What is the actual question, how to get rid of the abundance of nat, what I'm talking about - Pfsense puts nat, if you look at the beeline connection table, then there will be connections from 10.0. there, too, all connections go from 192.168.8.100 to the destination ip, how can I get rid of this so that all connections in the modem's connection table are ip from the destination in the local network?