So which city are we going to tear down and rebuild first?

It's not a good idea to tear down a city and build a new one centraly planned. Don't be Bob Moses. We want gradual, community directed, increases to the density of cities, and we want to stop building new stroads.

We have to come up with some new laws like you can only own a home that's within walking/biking distance of your work.

That's a bad idea. We should just tweak the existing zoning laws to allow high density everywhere, and mandate it in some places.

[Remote work] accomplishes most of what you propose

I strongly disagree. The commute to and from work should not be the only transportation need in a healthy life. People should also visit shops, visit friends, and visit parks. These trips should not require a personal car. Not to mention the large (majority?) number of jobs that absolutely cannot be done remotely.

The pandemic did not cause large changes in uban design, and absolutely did not make streets safer for pedestrians, so I disagree that remote work accomplishes most of my goals.