Ok, try the following:
- Uninstall waydroid-gbinder-config-mainline, neither hybris nor mainline is need
- If not yet done, perform (I know, you did it, but for the others)
devel-su waydroid init
to get the directory structure. The images will most likely not work
4. Test
waydroid show-full-ui
in the console, maybe twice. I had done this after I updated the images, so I can not test, what happens with old images.
- Get the Halium 12 images
images_url=https://sourceforge.net/projects/aleasto-lineageos/files/LineageOS%2020/waydroid_arm64
wget $images_url/system.img/download -O /home/waydroid/images/system.img
wget $images_url/vendor.img/download -O /home/waydroid/images/vendor.img
- Perform
devel-su waydroid init
It might stop and restart the container or return nothing. Both happend, took a couple of minutes.
8. Run
waydroid show-full-ui
Maybe even twice. And wait a bit. Lineage should boot up.
Even with the newer images, waydroid-runner doesn’t work, so no chance to start it from UI right now. However, waydroid might get started in the background, without access to the UI …
If there is a waydroid session running, e.g. after using waydroid-runner you can try
devel-su waydroid session stop
or use settings > waydroid and toggle the start button, this stops the session 
after that
waydroid show-full-ui
should work again.
Good Luck
Sources: Setup (and usage) is non-trivial under Halium 12+ (#24) · Issues · UBports / Development / Core / Packaging / waydroid · GitLab
and Sailfish OS Porter channel on telegram, thanks to deathmist
What is working:
Banking with DKB and Diba for example
What is still not working:
GPS after waydroid was started once …