Genuinely enjoyed the first seasons of both. Good acting, good directing, good set design, good pacing, good intrigue... and the fucking costumes in GoT. Every season they got better.
But so much of what was good in these series was the investment of a ton of time and effort and genuine love of the source material. Once that fell away in the later seasons, the shows just collapsed in on themselves until they were nothing but self-referenced tropes. Season 8 of GoT sucked because it was so obviously and disastrously rushed. It was clear the showrunners didn't want to do this job anymore, and it gutted the end product.
Dance of Dragons was a weak entry in the series and it showed. By then, it was pretty clear GRRM didn't want to write the main characters anymore and was working up entirely different stories in the margins. Getting away from the source material was Good Aktuly.