Yep, as said, just look for something that says "Add license" on your main Mogstation account, and enter your code/s there and all should be set!
And playtime is bound to the account, not the license, so as long as you link everything together your playtime will be exactly the same as it is on PC. Did the same but in reverse, I added a PC license to my account after having played on PS4 for over a year.

(Your UI and hotbars and gear sets will not carry over, though...)