Social Media is very successful in Get Out the Vote campaigns for younger people - who typically vote for one party disproportionately.
This one is already decided though. Biden on the Democrat side, Trump on the Republican. If anything it might hurt the Trump side a bit, as people may not realize that the Supreme Court only yesterday ruled states can not block him.
Can't you register the same day as the voting happens? Seems utterly stupid that you have to register to vote to begin with, but if it's a requirement, you should at least be able to register the day of the voting.
And states like Texas often have nearly one-party rule, so the primary pretty much is the election.
Because of the party that currently owns the non-urban parts of Texas, I usually vote in that primary, despite not voting for its candidates in the general elections.