I think the answer depends with which scenario happens.
Scenario A. BIden wins, but GOP holds Senate
Scenario B. Democrats sweep (worse case)
I think scenario A leads to nothing, Bidens first 2 years will be largely uneventful outside him magically resigning for health reasons and Harris becoming president. Scenario B on the other hand. I think the dems pass that 25th amendment thing aswell as a massive stimulus bill to look good. Biden is removed from office putting Harris as president with another hardcore leftist as VP (Warren likely). On top of all the radical socialist policies being adopted, we will see the Assault Weapons Ban with the best case being an exact copy of the original one. Worst case, they make it 1 feature and require registration under the NFA. I also expect a heavy tax on ammo. I also see under a Harris adminstration a packing of the court followed by immediate restrictions on the 1st amendment