General recommendation for Site2Site VPN setup

[polka44]

Hi everybody,
I want to create a Site 2 Site VPN between two households where IPv4 traffic can be transferred between.
Both households have a pfSense firewall acting as their firewall/router.
Household A has the german ISP "Kabel Deutschland" and is connected via IPv6 only. The connection speed is something like 32Mbit/s download and 6MBit/s upload. The LAN address of the pfSense is 10.0.0.1/24 . The pfSense is using an Intel Celeron J3160 with 4GB of RAM.
Household B has the german ISP "Deutsche Glasfaser" and has an IPv6 address and an IPv4 address with Carrier Grade NAT (CGNAT). The connection speed is 400MBit/s download and 200MBit/s upload. The LAN address of the pfSense is 192.168.1.1/24 . The pfSense is running as a VM on a Proxmox host. The VM has 4 vCPUs and 4GB of RAM currently, could be extended if needed.
So my question now is, what is the best solution to set up the Site2Site VPN?
Does anybody have a link to a suiting tutorial or something?

If you need more information please ask, im glad to provide everything i know.

[KOM]

@polka44 I'm not sure IPv4 will work behind CG-NAT but IPv6 should from what little I understand.

IPsec Site-to-Site VPN Example with Certificate Authentication

IPsec Site-to-Site VPN Example with Pre-Shared Keys

Site to Site VPNs on pfSense