I know I'm taking a risk of "getting political" but so be it.
What rich, traditionally conservative suburbs rejected Trump?
Will start with two examples: Bronxville NY and Dover MA.
Bronxville was thoroughly Republican until it voted for Obama in 2008 (it even voted for Goldwater in 1964). It went back to traditional Republican loyalties and voted for Romney in 2012, but firmly rejected Trump. In 2020 Biden got 70% of the vote in Bronxville.
https://www.myhometownbronxville.com...ntial-election
Dover was one of the few Republican-voting suburbs of Boston and one of the wealthiest towns in Massachusetts. Like Bronxville, it gave Obama a chance in 2008 but was firmly Republican in 2012 (56-43). In 2020 it went 69-28 Biden in 2020.
Then there's the Gold Coast of Connecticut. New Canaan was 64-35 R in 2012, 53-41 D in 2016, 59-39 D in 2020. Greenwich went 55-44 R in 2012, 56-39 D in 2016, 62-37 D in 2020.
Going to try to find some others.