If you use a synthetic wax periodically, you can keep the unpainted trim looking nice. The protectants like 303 or the stuff you mentioned works well, but requires more applications over the same amount of time.
Turtle Wax ICE or TW Spray n Shine are good products that are not overly expensive.
After many years, UV light will 'gray out' the plastic. At that time, a best course of action is to paint it with a flexible black bumper paint.
I personally never put any treatments on any of the black plastic trim on my CRVs.
Reason: 1) most plastics that will be exposed to sunlight now days on automobiles have specific stabilizers in them to protect from UV exposure. Such stabilizers are an integral part of the plastic and far superior to any surface treatments. The exception appears to be lights, as these must continue to be optically compliant clear plastics.. and these are much more difficult to treat for UV during fabrication. 2) After market treatments sold to consumers are really not that effective as they need to be applied regularly since they are surface level only treatments (some as often as weekly) and most owners don't do so.
Of course my vehicles are also garaged so they do not see a lot of long cycle sunlight or any weather extremes, but if they did.... I would use a car cover.. because much more than just plastics trim on your vehicle needs protection from the elements.. and not just sunlight either.
The only thing I apply any treatments to is the tires.. since rubber is prone to real degradation under UV and being slightly porous.. tire treatments actually do work well on tire rubber for UV protection.
Excellent comments from all. Thank you. This is my second EXL. The first was a 2008 that served me well. My new 2020 EXL is well appointed. Currently getting 30+ mpg city and 36 highway! Does Honda put synthetic oil in their new cars?