The Bird Zero29 is all of the things you say you don’t want pretty much:
64 degree headangle (unsagged)
80mm bb drop
76 degree seat angle (sagged)
Relatively long reach – although not absolutely crazy
I’d say go and get a test ride on one and see how it feels. Going up a wheelsize and more LLS than what you have may work great for you or it maybe too much.
I’ve done the extreme geo bit as far as I’m concerned and now dialled that’s back a bit as I know what I like.
Bird Aether 7 is now my fs bike and is near perfect for me (the bike being a bit lighter wouldn’t go amiss – although it has got robust build kit).
Hardtail I wouldn’t want those above angles / measurements personally. I know I have fun on something a little shorter / less slack / less bb drop etc.
* Marino hand built option above isn’t necessarily cheaper tbh – if you go with the cheaper 4130 and avoid all the options it still won’t be far off the cost of the Bird frame by the time you’ve paid to air freight it to the U.K. and paid whatever duty you get hit with it on (I’m ordering one on the basis I assume I’ll get hit for 20% vat but we’ll see).