All the fencing and securing of perimeters isnt to keep Congress locked in it's to make sure leftists don't riot and actually storm the capitol when it turns out Trump will be President.
Why fortify DC so heavily if you are worried about Trump supporters? Shouldnt they be deployed to different state capitals where the right wingers live? DC is 95% democrat.
I always thought the most strategic decision for Trump would be to declare martial law and hand ALL the power to a neutral group such as the military, not to install him, but to re-run the election to restore people's trust in the system. And if Biden (in theory) won, then I think most people, even on the right, would accept it as long as it's legitimate stupidity, and not a steal.