If Trump wins, still a big if, there will be rioting all over the country. Democrats will say Trump is an insurrectionist, and as such he is not qualified to be President.
They will try to not certify him, and try to get electors to flip like they tried to do in 2016 and 2020.
If he is certified, they will try to impeach him every month for the next four years.
If the left takes the House (they may), they will impeach him every month for the next four years and blame the Senate for him not being convicted.
And Biden will laugh and laugh and laugh.