First off, 64 and 86F are VERY different temperatures. I'm ideally in completely different clothes for those temperatures.
For the upper end my go-to is a 100gsm wool blend hooded shirt made by Voormi. I like it better than any pure cotton or synthetic options I've tried. On the lower end I'm probably switching to a 120gsm wool blend short sleeve shirt (they also make long sleeve versions) made by Ortovox if the UV index is low enough (basically just not high altitude).
Compared to cotton, wool does a better job with temperature regulation on both ends of the temperature spectrum. In warm weather it breathes well creating an efficient layer of material to aid in the evaporation of sweat to cool you down. There is a saying the "cotton kills" because of it's poor moisture regulation performance. In really hot weather (~100F) it is preferred by some people because it won't wick moisture which can feel cooling. Over an extended period of time though I find even at extreme temps wool to be better since eventually the water in the shirt heats up and the "benefit" of cotton wanes.
Compared to synthetics, wool will have similar performance, but I find wool to be much more comfortable feeling against my skin. There is definitely some level of personal preference here. Anecdotally I find wool does a bit better at the "shoulder temps" compared to synthetics where the breathability doesn't seem to kick in until there is already moisture. Synthetics can be a bit more durable, but wool shirts lasts me years and when they do need to be replaced are much more environmentally friendly overall.
Compared to both it doesn't get smelly which is a huge bonus. The only real downside
to wool in my opinion is cost. Some of the high end blended shirts have unbelievably high retail prices.
Another aspect to consider is fit. I prefer a slightly looser cut in warm weather.