Bed is loose from slide

[ColoradoKampers]

I can’t find any current pictures, or any that look exactly like my set-up, so I wanted to see what everyone’s opinion is. One corner of the bed has come loose from the slide wall. As you can see from the first picture, the obvious problem is that two left-most screws have pulled loose from the slide wall (the screws move freely in the wall holes). The 3 others along the 1x2 were still in the wall, but don’t appear to be holding very well. The other corner seems to be anchored soundly still. The 2nd picture is the upper half of the bed, the 3rd picture is the lower half (note the rollers mounted to the floor)

My solution is to use 4 L-brackets (4th picture) to fasten the upper rail which extends the full length of the bed “box” to the slide floor. I’m thinking I’ll put one bracket up fairly close to the slide wall, and then another fairly close to the edge of the slide floor (2 on each side positioned as shown in the last picture). The slide floor panel is 1" thick, so I'm hoping that a total of 16 3/4" screws will do the trick. This seems like the best way to secure the bed frame to the slide and to prevent the bed from shifting forward as others have suspected.

Comments, or better solutions?
Thanks!

NOTE: All pictures are taken looking toward the “headboard” and the slide wall.