The the LAN at 1 can ping 2 but not the other way around then your routing is probably OK and it's most likely a NAT or firewall rule issue.
There are a lot of troubleshooting suggestions for that sort of stuff at https://docs.netgate.com/pfsense/en/latest/troubleshooting/connectivity.html
But to boil that down a bit, you should check:
Look at the OS routing table on both sides, make sure there are entries for the opposite side LAN(s) and that those routes are pointing to the correct OpenVPN interface(s).
When you ping from the firewall make sure to ping from
both the OpenVPN interface itself (default source) and again using the LAN interface as a source. That tests routing between the LANs in both directions, not just to/from the OpenVPN interface directly, which is a much different test.
When pinging from a client on the LAN, look at its states under
Diagnostics > States on both firewalls, there should be two entries on each, one as it enters the firewall and one as it exits the firewall. If something like outbound NAT is catching it, the NAT would show in these states. If the traffic is taking the wrong path, that would also show (e.g. it should go in LAN, out VPN, in VPN, out LAN).
If the packets are exiting a WAN unexpectedly it may be from those clients hitting a policy routing firewall rule, so you might need to add a rule above whatever rule it's hitting to pass VPN traffic without a gateway set.
That should give you a better idea of what's going on and what needs fixed.
