It's the same: anyone who goes to Duat dies, and anyone who dies goes to Duat.
For example, both Osiris and Anubis each died once they willingly entered Duat.
Anubis died by going to Duat, according to what he says at the end of chapter 18 and his flashback in chapter 19: he went to the Nile river and swam until he reached the river of Duat, I think (I don't remember exactly where I read it, but IIRC, I read somewhere that the Nile and the river in Duat are somehow connected).
Osiris only had to give up his role as god of life first, because the god of life was the only god who was completely unable to enter Duat and was unable to die. We see in chapter 45 that he gave up his position as god of life in order to enter Duat and follow Seth, whom he mistakenly thought was already there (if Osiris hadn't given up his position as god of life, he wouldn't have been able to enter).
That makes so much sense! Thank you!! ヾ(❀╹◡╹)ﾉ~
Does Osiris need Seth to die so he would be send to Duat?? Or Seth could just walk/enter Duat without dying