Should work if the system won't start without a second connector. And theoretically each of those can carry 336W, so electrically okay. But we can't really be sure of the adapter wire gauge and if it is rated for your CPU's power draw (which I still don't know what that is)
I can't really say which PSU you have. In an ideal world you would get additional modular cables from Thermaltake. Or switch out the PSU to something that is actually designed for a high end system.
Thermaltake Smart series is not known for quality. If you have a big GPU in there (3080/4080/4090/6800XT/6900XT/7800XT/7900XT/X) I would reconsider using it long term.