npub18nddpdagql0nsh657exkj70r65glwtpywt3zlpc4v7d92dqmhtds93ax9z (npub18nd…ax9z) Might this be relevant? https://serverfault.com/questions/769374/firewalld-blocks-ipv6-ignores-config#comment1313551_775153
You might also want to see which firewalld rule is rejecting the connection, if you have that sort of logging available.