The problem that will affect your bike is not directly heat, but UV radiation from sunlight, and that does not only happens when the sun shines directly on the bike, scattered light from the sky and nearby objects will also have an effect.
UV radiation degrades polymers, plastics, rubber, and similar, sort of toasting them, making them dull, less flexible. I mention polymers because most likely that is what the bike's paint is made of, so yes, leaving the bike out in the sun all the time will cause all sort of problems to bike, from cosmetic damage to deterioration of seals, rim brake pads, hoses, cracking of derailleur pulleys, evaporation of lubricants, etc.
My recomendation is that you find a way of building a small shelter for your bike where it can sit not only in shade but in a very dark shade, covered from direct and indirect light. What Im suggesting looks a lot like a big dog house, probably made of wood and sheet metal (probably even lined with some insulating material), it doesn't have to be fancy.
Second alternative is some soft cover, like the ones used for motorcycles, but it has to be a high or medium quality one, a cheap cover may actualy do more harm than benefit. In particular, a cover should let humidity shed out, because otherwise the vapour will suround the bike, later condensating and causing corrossion in the most hidden and unlikely places.
I don't think any maintenance will compensate for all day, every day exposure to heat (and UV radiation), because radiation may reach deeper into the material than any conditioner, which almost sure is applied as a liquid or as a paste, thus acting only at surface level. It is also very difficult to thoroughly cover all the affected parts, not to mention laborious and time consuming plus that it would be necessary to perform it in a regular basis. It is more time and cost effective to find shelter for the bike.