Apologies if this is unhelpful but I would say the issue is the following:
Jun 08 09:28:52 vpn-iot openvpn [162535]: Cannot load CA certificate file /etc/ssl/certs/ca-certificates.crt (entry 119 did not validate)
Is there something you can do to validate
/etc/ssl/certs/ca-certificates.crt? I'm not sure how to do that myself, but that would seem to be the logical next step.