So another candidate that is not based how great can be as POTUS but on fear of how shitty the other candidate is. Just put a lettuce and say "vote the lettuce or Trump is coming". She can basically play the Trump card (no pun intended) everytime that she doesn't have arguments on her shitty proposed policies.
I don't know if policy disagreements are all that significant when there is a fundemental disagreement about the validity of democracy as a system of government.
The current Republican party is pushing an authoritarian political movement that rejects the principles of of liberal and neoliberal democracy that the US has been based on. The core issue that splits the two parties today is not policy, it is the political system itself.
Unfortunately that argument is too complicated for the electorate, most of which have no idea what a liberal democracy is, which results in a belief that this is about policy (back Ukraine vs not, tax vs no tax, progressive vs Conservative, abortion access vs ban, hawk vs diplomacy etc). Biden tried to make that point, but it just didn't stick and he just came across as a worried old man.
A lot of the "noise" around the election is concentrated around policy and value disagreements that are completely fair in a democratic system - but the most important difference is the fundemantal disagreement in how to run government, elections, presidential power, the international system and the role of the various branches of government.
In the US you have three main forces, two of which are driven by voters who haven't been helped by the neoliberal democracy model and one that fights for the status quo.
Two of them are in the Democratic party - progressive who want a return to classic liberal democracy and neoliberals or "moderates" who want to maintain the status quo with the belief that neoliberalism has secured US position as an undisputed hegemon. Within those two groups there are policy differences that put them left and right of centre - but there are almost no one arguing against the system. Within the Republican party the neoliberals have more or less been pushed aside by the authoritarian MAGA movement.
While the neoliberals and liberals all agree on principles about how the system is supposed to work - MAGA authoritarianism rejects those principles. As an ideology it is incompatible with liberal and neoliberal democracy. Therefore any disagreement on policy becomes essentially meaningless.
For instance; liberals and neoliberals argue about how much influence a president should have, MAGA pushes for unitarian monarchy. Liberals and Neoliberals disagree on specifics on abortion legislation, MAGA rejects the legislative branch. We see liberals and neoliberals disagree on who should vote and the structure of the electoral college, while MAGA rejects the very concept of elections.
How do you have policy discussions when faced with that?