In an ideal world, once Trump is out of office, we’d be able to remove all of his appointees.
Democrats can allow themselves to indulge in fantasies of impeaching justices (and even Trump himself) or they can ruminate over how things got to this place and, as you suggested, change their approach to get themselves back in the majority.
I’m not a Democrat. I just think that the only way to reverse the assaults on American freedom that Trump and his cronies have brought on us is to remove them from office. Things got to this place because Trump was savvy enough to appeal directly to the proud ignorance and stupidity that the Republican base likes while Hillary was too stupid and corrupt to appeal to what American voters actually wanted. To prevent this shit from happening again we need to abolish the Electoral College and outlaw corporate donations to political candidates and probably put in place some kind of IQ test requirement for people running for president so that someone as stupid as Trump can’t run again.
EDIT: Do you think Trump should be impeached for his blatant obstruction of justice? He admitted that he fired James Comey simply because he was investigating him. I know you’re very sympathetic to the far-right, so I’m guessing not, especially given how you ignore the legitimate reasons why Trump should be impeached.