I'm a certifiable "San Diego Comic-Con" geek and collected comics and read fantasy/sci-fi books. Without a doubt Game of Thrones (GoT) was the best show ever... well until the last season. I recommend watching it but be prepared to be highly disappointed for the final season. Is it worth still watching? I say yes as it's very well done for those first 5 seasons.
I used to rewatch it every year but stopped after the last season a few years ago as I hated that last season. I can't remember how much details were given in GoT about the past (events occurring during the House of the Dragon period) but I guess if you pay real close attention to what they're saying then it might be spoilers for knowing what happened in Dragon (beside the more obvious fact of knowing the outcome of a certain family... sort of like already knowing what happened to the ship in the Titantic).
Check out Bovada props for the Dragon:
Game Of Thrones: House Of The Dragon. Who Will Be 'The Hand Of The King' At Conclusion Of Season 1? Otto Hightower (-110)
Pure speculation but max bet is only $25.