Hello, As wonderful and amazing these 2 Tzaddikim were, did they do Hitbodedut as Rebbe Nachman talks about? If not, is it because they were on a very high level and can connect to Hashem very intimately? What was the highlight of their lives? I know the Chafetz Chaim and the Baal Hatanya HaKodesh spent 2 hours min. talking to Hashem in private.

I don't know, but if even the Chafetz Chaim famously did so every day and found it beneficial, it's definitely commendable, just like Torah study, for all of us "average" people!