Just did a fresh install of Atlantis + Sway Community. No video.
A quick troubleshoot shows incorrect permissions on a lot of stuff in /dev…
No access to /dev/tty*
No access to /dev/dri/*
No access to /dev/input/*
The access issue seems to be a combination of the default user not being in correct groups (input, video, etc), and the directories not having the correct permissions (no group write access to /dev/tty*, /dev/dri/*, etc.
I don’t think it’s needed to be in those groups for a normal user. When I install sway and create a user in arch I only put them into the wheel group for sudo. The rest is never needed. So I doubt it’s a permission issue. But that’s just my guess. I sadly have no idea how to go on about this issue, though.
Just to see if the problem is the desktop manager’s greeter, install sddm, disable lightdm, and enable sddm. If it works, you can either stick with sddm or concentrate on trouble shooting lightdm.
On the GitHub report you say using default configuration… But you installed the Community Edition or try starting sway without the custom config?
The C_E would have LY enabled per default.