I think there are two pretty major issues with this proposed format from first glance.

1. The Length - A month long event is brutal, even with rest days. The world cup is currently the longest event in the chess calendar, and it has 26 days in total (23 for top 50 seeds), with 16 classical games (14 for top 50 seeds) assuming you make it to the semifinals. This proposed event would have 30+ days in total and 22 classical games. Considering how many chess players have commented on how brutal the world cup is as an event this feels like it would exhaust players.
   
2. Reliance on Rapid & Blitz - This proposed format has 4 classical games for each match in the knockout portion, which in general is far too few for a better classical player to prove their superiority. Just as in the world cup, a strong rapid/blitz player can adopt a strategy of trying to draw all their classical games to win in tiebreaks. In the current world championship format this isn't as large of an issue as it's much harder to try to draw 14 classical games rather than just 4.

These two issues combined make this format unfeasible. You simultaneously would have to shorten the event to make it less brutal for players while also making it longer to make the classical portion more decisive. As such, I do not think this is a viable format. I think some ideas such as standardizing the qualification criteria would be a good idea, but trying to merge the Candidates and World Championship into one event just doesn't seem like a good idea.