Manually run /usr/sbin/iptables-restore < /etc/iptables/rules.v4 successfully so the rule has no problem.
Does qubes-service/netfilter-persistent limit the persistent?
# sudo systemctl status netfilter-persistent.service
● netfilter-persistent.service - netfilter persistent configuration
Loaded: loaded (/lib/systemd/system/netfilter-persistent.service; enabled; vendor preset: enabled)
Drop-In: /usr/lib/systemd/system/netfilter-persistent.service.d
└─30_qubes.conf
/etc/systemd/system/netfilter-persistent.service.d
└─iptables.conf
Active: inactive (dead)
Condition: start condition failed at Sat 2022-03-26 11:32:20 CST; 3min 27s ago
└─ ConditionPathExists=/var/run/qubes-service/netfilter-persistent was not met
Docs: man:netfilter-persistent(8)
Mar 26 11:16:28 localhost systemd[1]: Condition check resulted in netfilter persistent configuration being skipped.
Mar 26 11:26:52 proxy systemd[1]: Condition check resulted in netfilter persistent configuration being skipped.