There will still be a Hex, but the participants are determined by the top six in the FIFA rankings (currently Mexico, US, Costa Rica, Jamaica, Honduras and El Salvador). The Nations League will go a long way toward determining the bottom 3 of the Hex.
The top three finishers qualify for Qatar and the fourth place finisher plays ... (see below)
The 29 remaining members of the confederation play in eight groups. The 8 group winners are drawn into home and away knockout rounds with quarterfinals, semis and a final.
The winner from the Group of 29 plays home and away with the fourth place finisher from the Hex. The winner of that plays home and away with a team from another confederation and, if they win that, they qualify for the World Cup.
The good thing I see about all this is that the lesser confederations now have a number of meaningful games being played almost every year. Prior to now, they would cobble together a team to train and play a home and away World Cup qualifier and then sit around until the next qualifying cycle. It will be easier to recruit players to the teams and, hopefully, will strengthen the overall quality of the confederation.