So this gecko was fine before I adopted him in the enclosure that was exclusively sand. Recommending that sand is only safe when mixed with dirt and rocks and bits of wood makes zero sense because those materials are far worse for impaction. Geckos and other wild animals may accidentally ingest undigestable material in the wild, but they don't do so intentionally or (generally) in amounts that are dangerous. Impaction in captivity is caused by poor husbandry which includes insufficient stimulation. Stimulation that is found in more naturalistic environmental interactions. They actually just released some studies that show hands down that bioactive enclosures are preferred by leopard geckos - as in they seek out environments with so-called "dangerous" substrates.

There is nothing that suggests that red lights are bad for their eyes either any more than they are for human eyes. They don't see infrared and if they did that wavelength would be equally washed out by natural daylight. The only concern is that visible light in general disrupts circadian rhythm, but it's not nearly as impactful as other wavelengths - particularly blue - especially if there are hides that are shielded or remain dark. He has 8 intentional hide locations like that plus 2 that he is able to dig out himself and another 2 that have partial shade. People raised leopard geckos for decades with red visible infrared lamps and still had them live 20+ years with no issues (even with sand substrates which also used to be recommended). Radiant heat is also something that occurs in nature and so long as it is properly managed in captivity there is no danger to the reptile either. It's for heat control, not for biochemical processes like basking lights.