The determining factor is whether or not the child provided more than half of their own support in 2021. The comment that the child could make a million dollars and still be claimed by their parents meant that as long as their parents continued to support their child, it does not matter how much the child made.
In your case, it seems as if your daughter does pay more than half her own support, therefore you would not be able to claim her as a dependent on your tax return. The IRS provides a worksheet that you may find useful to determine if your daughter does provide more than half her own support.
One argument you could make is that if she is renting from you, the fair market value of the housing you provide is much greater. Therefore, in essence, you are providing support for the difference between what the fair market value of the rental is and the amount she is paying.
@jenrysdam
