I suspect that they stayed home out of a mix of disgust for the entire process and people,
If you ignore a problem it doesn't go away. It just changes and it usually gets worse, often times much worse.
and also there was a pandemic ongoing that in some parts of the country was at the time non-trivial.
Absentee ballot? Colorado has supported mail in voting for anyone that chose to for a number of years. Deb and I have been voting absentee for about six or seven years (62 used to be the age limit). Just before the pandemic a state ballot proposal opened this up to anyone that is of voting age can request a mail in ballot without requiring a reason. Plus you don't have to mail it back in, you can drop it off. Our township set up a drop box outside the township hall right next to the box where you drop off your taxes, water bills, parking fines, .... (aka treasurer's stuff).
Despite this last election being one of the heaviest voter turnouts in just over a century (65%) it still lags behind Sweden (82%), South Korea (77.9%), Israel (77.9%), Germany (69.1%), and France (67.9%). We have lower voter turnout than Mexico (68%).