Which link? If you’re looking for CC signup bonuses, this DoC page gets updated. Plastiq got bought by another co recently and might still work, but I haven’t used it in years. For churning, I pay property and income taxes with CC fees in the 1.85-2.3% range vs Plastiq’s 2.9%.
If you’re asking about mortgages in general and not for CC churning purposes, there are a few ways to pay mortgage with rewards debit cards, see the discussion here.