I think whether you think it is a "tank" depends on a couple things. First, if you think Rattler has a shot to be as good or almost as good as Carr. And second, if you think the terrible record last year was mostly about injuries and this is essentially a .500 team. If you think both of those things, and I mostly do, it also seems like just adding low priced free agents and draft picks, while moving on to another QB, would be good enough to keep this team competitive and not tanking.
We don't know what they want to do with Carr. And, I'm not saying they are "desperate" to move on from Carr. But, the fact that Moore didn't say he is my starter or he is my starter this year tells me that the team is at least considering moving on from Carr this year and are not fully committed to him as the starting QB this year or in the future. Moore may be okay with starting him for another year, but he is clearly not chomping at the bit to try to fix him. Otherwise, again, he would have said he is my starting QB.
If the cap is $10 million higher or even $5 million higher, that makes it much easier to move on from Carr this year if they want to, while having a little money to upgrade a key position or two which would look even less like tanking. It might even give them some money to sign a guy like Fields, Daniel Jones, etc. as a reclamation project that Moore may be more interested in.