You should be able to see what OPNsense blocks from the firewall log.Maybe something is wrong with your rules on the OpenVPN interface.
from the log-- "The rule that triggered this action is:@63 pass out log route-to (em0 192.168.101.1) inet from 192.168.101.183 to ! 192.168.101.0/24 flags S/SA keep state allow-opts label "let out anything from firewall host itself"
pass in quick inet from your_openvpn_net/netmask to any