Just a brazilian physics student.
Yes, I remember reading about a gtk thing that interacts with flatpak, they said it should not give this error in April, but it seems to still be happening, idk.
Edit: I just saw that you deleted the gtk portal and it worked! So no need to install another dbus daemon.
I installed dbus-broker and the package manager checked the dependencies and removed the unnecessary stuff. After that I applied the dbus-broker services:
systemctl enable dbus-broker.service
sudo systemctl --global enable dbus-broker.service
And then restarted.
Idk if it might break things in mint, so I would be cautious.
I had this problem with flatpaks, I changed the dbus implementation to dbus-broker (in endeavouros) and it fixed the issue. It may be the same problem.
I use msys2 (https://www.msys2.org/), it uses pacman as its package manager and has a lot of developer packages (so i can compile fortran and integrating it to python). It comes with bash and a terminal, but I used windows terminal and made a profile for using msys2’s bash, the same on vscode. Then I installed neofetch (https://packages.msys2.org/base/neofetch) and just saw this hahaha.