I'd add one nuance.
Just like older white working class, black & Latino working class older folks are socially moderate. But that is not the same thing with younger AAs. They also support Bernie over Biden.
That is a bellwether for the future, but it is less important for 2020. Older African Americans are a very reliable voting block for the Democratic party. Like most young people, younger people of color turn out in fewer numbers than their parents and grandparents. States that make it easier to vote tend to have higher youth turnout rates than states that make it more difficult.
I came across this:
CIRCLE » 2018 Youth Turnout Increased in Every State for Which We Have Data
and this
CIRCLE » Final Analysis of State-by-State Youth Voter Turnout Shows Increases Across the Country
In 2018 Oregon, Washington, and Colorado were 100% vote by mail (Washington offers an in person voting option, but basically you go to your county voting office and fill out your mail in ballot there). Hawaii starts mail in voting in 2020. In 2018 the turnout in these states was high: OR-39%, CO-40%, WA-35% and there were few key races in any of these states. There was an outside chance to unseat two Republican congresswomen in Washington, but it was almost guaranteed that Oregon's delegation was going to remain the same mix. The one Republican is in a super safe seat and it was unlikely any Democrats were going to lose seats. Some states with big races like Florida and Georgia saw big youth turnout increases. Many of the states with low youth turnout are states where Republicans have made it more difficult to vote.
Until I saw those articles I didn't realize how much the youth turnout had increased in 2018, but I do recall reading stories about how the turnout in 2018 more matched presidential election years than midterm years. I wouldn't expect similar increases in the youth vote from 2016 to 2020 because a lot of the increase was in populations that didn't vote in 2014, but voted in the same numbers in 2016 and 2018.
In any case, the country is definitely poised to move to the left over the next 20 years. Possibly more than it did in the 1930s, but the Baby Boomers are still a significant voting block and the Silent Generation still has an impact. The Millennials now outnumber the Boomers, but Boomers are much more reliable voters so Boomers are still the most significant voting generation. That will change soon, but I would be very surprised if it happened in 2020.