Those are obviously incorrect if the purpose is to allow access from external systems to specific port on your system. They are mostly harmless, but they are useless for your stated goal.
iptables -I OUTPUT -p tcp -d 172.19.0.3 -j ACCEPT
This may or may not be needed depending on other firewall settings. Usually outgoing packets are not filtered by default at all.
nft list ruleset
iptables and nftables are two different kernel subsystems. Rules configured for one subsystem are obviously not visible in another subsystem. You provided no information what you are using currently.