Is it possible to attain the ranks of the Companions and the righteous through a single act, such as going early to Friday prayer and seeking the reward for every step as a year's worth of worship?

None of those who came after the Companions can attain their ranks, even with all their deeds. Most scholars are of the view that every single one of the Companions is superior to anyone who came after them. This is because the faith that was in the hearts of the Companions when they spent [in charity] in the early days of Islam cannot be replicated by anyone after them. As for the righteous among those who are not Companions, a person may attain their rank through one great deed performed with sincerity to Allah and with humility before Him.