This is a difficult one. I purchased the course because I've begun my journey of learning Godot and hoped the course would soon be updated to Godot 4. In the meantime I hoped to glean something from the course as it currently is.
Naturally, I would like to see it updated, but I also understand it's a monumental task. Whether you update it now or update it later, it seems the workload will likely be the same. It also seems to me it would be better to update it now while Godot 4 is new and then make incremental updates as Godot is updated. The incremental updates will likely be required whether you update now or whether you wait, though I guess you are hoping there will be an LTS release soon.
Obviously, I'm biased but I would like to see it updated soon, so I can learn from it sooner than later.