While the 1999 version has the old aesthetic that you say you like, I would recommend the 2011 version due to a lot of times just presenting individual scenes so well, the team really came together to make dramatic when it counted, and it also goes further into one of the best arcs of HxH
Nippon Animation did 1999, while MADHOUSE did 2011 if that says anything to you
One thing I had heard is that the Manga has been on a really long hiatus. Does 2011 end in a way that feels pretty conclusive as opposed to like a cliff hanger?
Anime does end on a really good note. The good news regarding the manga is that the writer has started again, so fingers crossed for more anime one day ... And best of luck to his continued health.