An extra long closet and the rod, mounted in concrete, keeps falling off.

I have an antique chifforobe that is only 16" deep. I purchased 'petite' or kids hangers from Amazon. they are 14" wide and big enough to hold most adult clothing. Bonus, they are very thin and flocked so that your clothes won't slip off.

Usually 2-feet is the minimal depth or 1-foot on either side of the rod, more is better even if it's just an inch or 2. In your case you can do an upper & lower rod at both the front & the back of the closet, without any need for center supports.

However, no rods nor sockets nor anything should be just screwed in anywhere. They have to be screwed into the wall's framing studs. You probably won't find studs where you want to have the rods.

So, what needs to happen first is that full depth of the closet wood slats or slating need to be screwed to the walls at the stud locations. These slats or slating now become your nailers or screwers & only into these will you put any rod or socket screws to then have the rods wherever you want them.