You're not thinking this through..We have compulsory voting in Australia and how it works is that if someone is pissed off that they are forced to vote they don't vote, they just turn up have their name ticked off and that's it. Or they go into the booth and put a blank paper in the ballot.
Compulsory voting does not make people who don't want to vote, fill out a complex form correctly.
It is you who haven't thought it through. Or maybe you have and you realised that not having compulsory voting leave so many options and avenues for voter suppression.
Trump said the small print out loud when he clearly said that if everyone entitled to vote was allowed to vote the Republicans would never get elected again. And that's cirtainly true, UNLESS they modified their platform to reflect the voters' intentions. But Republicans are not for democracy obviously. Just look at Barrett, it's been 4 years and 7 months between the deaths of Scalia and Ginsburg, yet in a four year term Trump has replaced both. Not only that but Barrett is a Federalist society hack and religious nut job who represents about 30% of the US's desires.
If the electorate delivers a Senate Majority to the Democrats along with Biden, they will have a mandate to repair the US fragile almost democracy. Because the US citizens know full well that electing Biden, is not enough, they know he needs the Senate.
I predicted at the beginning of the Trump Presidency that it will be a good thing for the US long term because there will be a massive correction. The Democrats have been way too timid, but after the excesses of the Trump administration they will certainly right the wrongs, and they'll have a mandate to do it.
No one is going to forget Lindsey Graham saying, "hold the tape".
Installing Barrett because they absolutely know the voters who are already voting do not want her, is another form of voter suppression that lasts for 40 years. Which is way the GOP are willing to sacrifice their majority in order to get her on the Court.