i envy you.
season 8 caught a lot of shit, but really, the show did a great job of condensing a GIANT series into a tv show. but in doing so, they inevitably had to cut a ton of shit out. they combined multiple characters into a single character in the show etc etc.
the books are great, and theyll be different enough to you to keep you very much into it.
and as far as GRRM being able to finish them.....he has one literally on the presses ready for us to read. the others, who knows. but like most authors, he probably has someone(s) lined up to finish them in the event that he cannot.