The US's strength is/was in part because of immigration. The best and brightest want to come to the US to go to school and then they often stay for the enormous opportunities only available in the US. I want any immigrant that wants to come to the US given a reasonable path to make that happen.

You are right that the Native Americans were completely misplaced by immigrants, but immigration made the US what it is today and I see no reason it won't continue to make the US a uniquely strong country.

You may be interested to learn that American immigration flows were higher or lower at various times (nearly zero for long periods). As you allude to with Native Americans, the effects of the different flows were not uniform on all people, and instead caused various negative and positive effects. The period of Americans great post-WWII economic and military rise came during its longest period of immigration moratorium, during which its population was fairly homogeneous. In recent decades, America has begun to decline economically and militarily relative to China, a country not subject to these "strengthening flows". Odd case.