So glad you mentioned this! I actually use this site SunFlight.net - Day and Night Flight Map to check where the sun is during my flight, because I like the window seat but have a sensitivity to direct sun, and which side the sun is on does matter to me esp. during those times of day you mention.

(and now that I think of it, there are actually many factors to choose a particular seat vs another even though they may seem “like for like”, e,g. one side will have a particular view of something, or a row is missing a window. Might seem trivial to some but not to others)

Once someone asked me to trade a seat (I think I had a window) on a transcon in order to sit with his daughter and I agreed to it. I *assumed* he also had a window if he were asking to trade, but actually he and his daughter both had middles! Needless to say I was quite irked, and from then on I always double check which seat someone is asking me to change to even if it feels awkward.