There are several error messages displayed for the various possibilities.
You are not seeing this
Steam DLLs not present or failed to load!
which would happen before the Steam subsystem is enabled to verify the DLLs are present. So presumably the first problem “dlls in right place” is not the issue. The next hurdle is that Steam is trying to initialize itself but is being rejected with a
Warning: STEAM: Steam API disabled!
A quick look in bool FOnlineSubsystemSteam::IsEnabled() shows that is checking to see if you have the DefaultEngine.ini setting
[OnlineSubsystemSteam]
bEnabled=true
which you say you’ve added, so the last and final part of this is the check to see if you are running the game or dedicated server and NOT the editor itself.
if (bEnableSteam)
{
bEnableSteam = IsRunningDedicatedServer() || IsRunningGame();
}
Which if you are trying to launch the editor then play in “Play In Editor” for example, you will have Steam disabled. If you run the editor with -game or -server you will then be able to use Steam directly.
You can also remove this check so that Steam is enabled in the editor. The reason it was disabled by default was that people didn’t want to have the Steam client open to run the editor and/or see the “user is playing GAME” messages from Steam presence every time an artist/coder started up the editor (and maybe you don’t want to show non dev friends what you are up to as well).
I hope this is your issue, happy to take it further if you run into more problems, and sorry if this kind of warning is unclear. Let’s get you past your troubles and we can talk about how we can improve this afterward.