LED Floodlight Recommendation - Solar?

I was going to swap out one of the standard contractor installed lights on the side of my garage door for a Lithonia 150W equivalent LED dual head floodlight. When I removed the existing light fixture, there was not a junction box behind it. The electrician screwed the mounting hardware to the wall and there’s a small hole for the wire to come through. The replacement LED floodlight was too shallow to hold the wire and wire nuts and could not be installed.

I’m guessing I should just leave that existing light as is and try to find a quality solar LED floodlight? Any ideas on a good quality solar floodlight that will last? Thanks!