I think there's a little more nuance to 'tear down' or not when it comes to guys like Miller and Schmidt. When you're rebuilding, the most valuable asset you get is your own 1st round pick. Trading guys like Miller and Schmidt for futures statistically you're not going to get anywhere near as good a player in return. For example, what we gave up for Miller turned into Hugo Alnefelt and Shakir Mukhamadullin. When your team needs a reset you trade these guys to help ensure you stay in the basement for a couple seasons to maximize value on those top picks who will be the core of your future team. The lesser future assets you do get can be used for targeted trades when your team is ready, and as a lottery chance that 1 in x will actually amount to something good.
So basically, if you want to reset and put the team in a tank for the next 2 or 3 years after this one then yes start trading Miller, Schmidt, even Horvat. I don't think that's smart though. The young core should be ready to push ahead now, Benning as usually just made a huge mess years in the making. Rather, I think the plan if the team had competent management should be to write this season off as a loss and get what you can for your UFA's, take the high pick, and continue building on this core replacing Benning's specials as their contracts expire with effective but lower cost players. If done right the 21-22 season we should have a reasonable bubble team but the target is to be good by 22-23, ideally with our 2021 1st round pick having an impact on a 3 year ELC.
Also I should add if Miller is unhappy here then you can look at trading him, just more of a hockey trade than a sell. Don't forget players with high salary and term aren't highly valuable these days, like Schmidt only cost us a 3rd.