Trump has forever lowered the bar. Very few people who voted for Biden want him to play by different rules than Trump played by. We have had enough of taking the high road ****.
The big difference between what Biden is doing is that he actually won in a landslide whereas Trump has never once gotten more votes than his opponet. Never even eclipsed the low bar that is 47% of the vote. Should a significant minority of the country be making big changes? The justices issue was a big part of the Republican campaign for both the Presidential election and two senate runoffs in Georgia. You lost all 3. Adding justices probably wont happen before the 2022 election so you still have a chance. If you lose yet again while running on the issue I cant see how it is not the will of the people.