How different a ride is the 2.8 Trailblazer compared to say the 3 Chronicle (I am talking in terms of feel from the volume as opposed to differing tread patterns etc)?

Difficult question to answer, there's certainly a difference but you might find there's more of a noticable difference adjusting pressures on the same tyre.

Ok, Interesting!

If you are anywhere near Stansted airport, and ride a size large, then you are welcome to have a go on my stache ;0)

I have a 29+
It is comfy.
It is quick once up to speed.
Less tiring after a long (by my shonky standards) day in the saddle.
However.........
With hindsight, a nice sprightly steel 29er with widish rims and 2.4 ardents would suffice for most of the terrain I have so far encountered.

Maybe I just need to move somewhere rockier and sandier.

I am not looking to change my bike.
If I was building a play bike I would
go 650b+
Race bike, 29"
Bike packing bike 29+ probably
Also, I am not tall.