I’ve setup a Manjaro virtual machine with VirtualBox, with bridged network adapter, I’ve installed archtorify, I’ve enabled tor with
sudo systemctl enable --now tor.service
and then I’ve done sudo archtorify -t but I keep seeing my own ip when I run sudo archtorify -s.
How can I get the virtual machine to run all connections through tor?
Why?
Using some random person’s script on GitHub without knowing what it does seems like it defeats the purpose of your end goal of perhaps being secure using Tor in a VM.
Either way, there are many guides online. Why not use BlackArch, Parrot or Kali?
The alternatives I’ve considered are Whonix and Tail OS, but only if I don’t manage to do it this way, because they are Debian based and I’m just used to Arch based systems.
That’s just an assumption. The program automates the steps for Transparent Torification from the ArchWiki.
Oh, I guess you already know better then. 
BlackArch and Kali are pentesting systems. They don’t have tor setup by default like the systems focused on anonymity. So I’d have to do the same with them I’m doing now.