That's actually not a bad breakdown of how this could go. It's also entirely possible that the 4th season, if it were to be the season that wraps things up, could just be 2 episodes like AL was, and this would actually be very much preferrable.
Things have been moving very fast for the MC so far and, whilst some might argue against it, I feel like we could see some sort of time jump after this Scavenger Hunt week is over. It would make sense to me to do this because, if the MC's life settles down into something of a routine by the end of this of this upcoming week and other plot threads are given a brief respite as well, it would allow the story to advance without the need for intervention by the players until the next dramatic story beat, which would likely be the MC's birthday and finding out what's in that letter.
Hardware advancements aside, there's still the man hours required to pose the models and make the animations which is still the longest part of development. Not to mention the development of the free-roam and mini-games, and DPC seems to like adding new types of mini-games and this will also take time.
DPC has also been upping the number of renders and animations by quite a bit with each episode, so I'd expect this to continue as well and that means more time spent posing renders and making animations.