/etc/pam.d/sddm-autologin requires pam_tally2.so, which breaks autologin
As the title states pam_tally2.so is set to required in /etc/pam.d/sddm-autologin which results in autologin not working, you'll instead be stuck with a blackscreen. A quick look inside /var/log/messages indicates that this library doesn't exist.
I have therefore set it to optional and that seems to fix autologin.
Is this library even relevant to the autologin feature?