Uhhh... hate to tell you this, but Cuban absolutely tanked in that exact position so they wouldn't have to give up that pick to New York that turned into Lively. You don't think Cuban was on board for that? Even when the Mavs were at the end of the Dirk era before they got Luka, Cuban was quoted as saying that they were going to suck for a good while until they were able to find another star and build it back up.
With regard to the path forward... I would not tear down to the studs. It doesn't make any sense to if you only control your own first round pick for next year. I have some news: this team is going to lose a shit load of games as long as Kyrie is out, just about no matter what else is done. It's a roster construction that was build around Luka, it makes no sense as is. So you can call it a tank, but it's really just a bad team in a tough conference. The Mavs are going to lose, and lose a lot.
So, suck this year, hopefully get lucky again in the lottery, move some pieces around if you can get some value, then run it back next year with a healthy Kyrie, more experienced Flagg, maybe a healthy AD (lol), and some retooling around some of the role players. Depending on how Flagg develops, you can put together a pretty decent team going forward out of it.
One more thing... I've been watching a few Mavs games (more than actual Mavs fans it seems) and it's annoying as fuck how your announcer constantly refers to Cooper Flagg as "Coop". Call him Cooper, fine. Call him Flagg, fine. But Coop sounds fucking stupid. Is your play by play guy an Aggie?