That is also normally my rear tyre of choice (27.5 though) but you wouldn’t get one even if you offered up your first born.
I went for a Schwalbe hans dampf super gravity instead and it seems good so for won’t be as grippy as a DHR but it rolls a hell of a lot better. Perfectly good for the summer and it still has quite a tall side nob.
The super gravity casing felt slightly thinner than the DD but not much still feels a lot better than single ply versions. Double down is still a dual ply casing just it’s 120tpi and DH casing is 60.
According to the maxxis website and a bike radar review the SG schwalbe is lighter than the DD maxxis by 100gs or so. The big Betty is heavier and looks like it would roll slower than the dhr so I’m not sure I’d go for that.
Keep checking at the bike shop sometimes stock has been arriving spontaneously even though the due date is next year or something stupid.