I would suggest you focus on outgrowing the need to be proud of your nationality. It’s not necessary to be able to wave a flag happily to live a good life, do good things with your time, and appreciate others who are doing the same.

The second you try to take this to the level of the entire country, and specifically the nation-state itself… now you’re into a whole mess. The US has a lengthy history of atrocities, toppling democracies, massacring innocents, dominating weaker groups… just don’t go there.