Both will require two different approaches.

The first will be someone who has been tricked by the media into believing Trump stole the election in a grand conspiracy -- to them a de facto tyrant. Their position will stem from misinformation, propaganda, and good old trickery created by the media and propagated by social media. The important thing to keep in mind is that this person has a mislead worldview, but intends to act morally. They will demand action because they are motivated to stop an evil, but, unfortunately this mislead worldview leads them to find evil where there is good and good where there is evil.

The second will be someone who was gleefully awaiting the new world order as a "useful idiot" on the promise that socialism (which we know better as simply communism) will fix all of his/her woes in life. To this radical, anything is justified so long as it brings about the new order. This person has a deeply flawed conscience, an inability to see good. He/she can therefore only act on human instinct (the body being of flesh and mortal, is devoid of the higher principles of the conscience). This person has resolved his/her inner struggle by lashing out at the "Bourgeoisie" and blaming others for personal strifes (the government, the patriarchy, capitalism, etc.).

The first kind I suspect will be in the minority of Biden supporters, though still common enough that it will not be rare. This first person I would call akin to a cannon pointed in the wrong direction. He/she possesses the ability to fire (to reason), but he/she is guided to the wrong target. One must accept this is a person acting on what he/she believes is right. The goal is to demonstrate the morality of your position, the validity of your statements, and, most importantly, the invalidity of his/her statements. This means education (both of ourselves and the person). You must be well versed in your positions and be able to substantiate them. Become familiar with objections and how to overcome them.This is a person I would consider worthy of intelligible debate and deserving of the courtesy in such a setting.

The second kind, the Marxist, has been radicalized to a cause outside morality, and does not look for guidance therein. To this person, morality has become an inconvenient source of personal pain. Unfortunately, this person is unlikely to listen to anyone outside his/her circle, so encountering a stranger is simple survival as this radical has proven to be likely of bodily harm. Don't waste time on debate if you do not know this person. Instead, keep yourself safe (stand by and stay ready, but never instigate). Forgoing pride will be the greatest challenge here as this radical will likely taunt you into engaging in his/her immoral tactics.

Do not take my more disparaging tone of the second to mean I view them as less human. They are, but rather, in a darker place than the first. I feel more disheartened by the length they have fallen and by how insurmountable it can be to climb back from there. The only effective measure against the second is that he/she learns to forgive his/her-self, to let go of his/her own faults (please tell me if that sounds easy). This, I suspect, cannot be influenced by us, but only by close associates, so we must do our best to set a good example as that is likely the extent of our effects. Naturally, protect your life, liberty, and property in the fullest measure required by God should this person decide to violate your rights.

TL DR: Remember some people can be reasoned with, while plenty, I believe, will be radicalized and are not worth debating.