Republicans only had a majority in Congress since 2014. Four years, not eight and it was never a supermajority like the Democrats had
Secondly, while the Republicans had a majority in the Senate, it was only by 2 votes. Since most things in the Senate require 60 votes to pass, the Rebulicans still needed a bi-partisan vote. With the Democrats irrational hatred of Trump, they were, and still are, obstructing anything that would look like a win for Trump. No matter if it is the right thing for the country.