Do you think USA is wrong to help Taiwan & Ukraine?
No, unless it oversteps and turns its help into hostility. Its help in Taiwan should be purely defensive, which it has been so far.
Or that USA has wrongful motives in doing so?
Are geopolitical interests "wrongful motives"? I would say that depended on the context. It's possible that at least some officials believe in helping other countries to maintain said countries' democracy and independence, but the bigger picture seems to me primarily about geopolitical interests and keeping global rivals (China and Russia, in this case) at bay.