They (DNC leadership) are already pushing him onto the ballot before the convention under the guise of meeting the Ohio ballot requirement, while ignoring that Ohio gave them an exception for the convention.
There is still concerted effort from both within[1] and outside the party[2] to push back against rushing the process. His fate is by no means guaranteed.
While there's almost certainly an element of "let's get this done and over with before the push to switch out Biden grows even larger," Jamie Harrison's explanation[0] would suggest that there's still a very real legal concern behind the push. Specifically, this little nugget[1] from the Ohio Constitution:
> [...]No law passed by the general assembly shall go into effect until ninety days after it shall have been filed by the governor in the office of the secretary of state, except as herein provided.[...]
So while Ohio eventually passed a law that would extend the deadline to avoid the original problem, because it wasn't done passed as an emergency law not subject to referendum[2] since that would have required a 2/3 majority, that law doesn't actually go into effect until 90 days after its passage.
In other words, the law changing the notification requirement from 90 days prior to a general election doesn't actually go into effect until 90 days after its passage...which is after the original notification deadline. It might seem like a technicality, but it all but guarantees the issue will have to be litigated and there's a significant possibility Democrats would lose the case in that case. Risking the possibility of Biden being left off the ballot as a result would be an absurd dereliction on the DNC's part.
The original post asked what can you do. Apart from hopelessness, you can put your body on the line. Hold a sign. Be present. Take up space. It's something.
Biden could be a literal corpse come election day and his cabinet/admin will still not paywall NOAA so why does that matter?
Both Trump and Biden are abysmal picks, for rather different reasons, but come November 9th, one of them will be chosen as the winner, because that's how the American electoral system is designed. If you don't like either of them, it doesn't matter. They still have explicit visions and plans for the future of the country, and surely you like one more than the other right?
People need to get this "perfect candidate is the enemy of the least-worst candidate" shit out of their head. The American political system was designed by a bunch of ethics and philosophy turbo nerds with an insanely optimistic view of how humans organize, a blatent neglect of already understood problems (refusing to create a term limit for the presidency even as Washington was trying to avoid being president for life, choosing to take no preventative action against the formation of political parties despite them obviously forming before the constitution was even finished, no formal system of succession, even though politicians were still dueling each other), and zero systems engineering or practical experience. It is flawed in all the ways you would expect a student project from first timers will be.
This stupid system is the one we are stuck with, and by design it can only be changed by participation, unless you are fine with murdering half your neighbors to enact a populist revolution and also convince everyone else to murder half their neighbors in your populist revolution.
Staying home isn't a protest. Not voting doesn't hurt anyone but yourself. Choose the direction you want the country to go in.
Call your congresspeople and demand that they put a candidate on the ballot that can make a coherent case against this policy.
Backroom discussions are happening right now to determine whether or not Biden will be replaced by someone that can actually win.