Hi @Kevin,
I have just found a solution.
Basically, I re-installed a brand new server installation following strictly to the instructions in How to install & setup Ghost on Ubuntu 20.04 or 22.04 (The official Ghost-Ubuntu Installation Guide).
All in all, I guess my issue was the manual change from localhost to 127.0.0.1 did not work and a fresh installation clears up the issue altogether noting that the usual localhost placeholders will now be switched over to 127.0.0.1 to resolve the issue while using node 18 and above.
In addition, do ensure that the server instance being used is running on ipv6 as well.
Hope this helps someone else facing the same issue! Cheers! ;)
OS: Ubuntu, v22.04.3 LTS
Node Version: v18.18.2
Ghost Version: 5.74.1
Ghost-CLI Version: 1.25.3
Environment: production