There are now reports that some Democratic members of Congress are planning to boycott the inauguration. It is totally understandable why they would consider passing up what, under normal circumstances, would be a celebration of democracy and the peaceful transfer of power.
Suggestion:
Democrats and other patriots could transform it into a protest. They could carry signs reminding the American people that Trump is an ethical nightmare and a criminal. They can even cause a peaceful disruption when he attempts to lie about preserving and protecting the Constitution.
One could also follow up the inaugural ceremony by remaining at the Capital after Trump leaves to pay tribute to the law enforcement officers who were injured or died as a result of the January 6th insurrection that he incited. And they could also incorporate a memorial to Martin Luther King Jr., whose holiday coincides with Inauguration Day.