Rich usually runs cool(er). Don't think that is your issue.

Hot at slow speed and cool running at higher speed usually means inadequate air flow. Fan + shroud (hopefully shroud!) not enough.

Can you share some detail on your current fan/shroud setup?

PS: some heating at a stop or low speed is expected. 210 F I think is fine, 220 F some concern and 230F getting too hot for my taste. An after market mechanical temp gauge may help figure it out.