Try this from geometry geeks – I’m assuming they have all the figures in correct – the latest version of the Sentier / Scout / Transmitter / Switchback in a geometry comparison.

Maybe have a play about with the site comparing bikes then make a shortlist and see which of the frames is available right now. As you referenced a long seat tube I’m assuming you’re looking at large frames as a few seem to have a higher seat tube length jump between medium and large:

https://geometrygeeks.bike/compare/sonder-transmitter-2021-large,vitus-sentier-27-2020-l,stanton-switchback-gen-3-2020-18,nukeproof-scout-275-pro-2021-large/

Re, the sonder transmitter
i found it to be an aboslute beast on the downs and an excellent climber, i didnt find it any more playful than the DMR trailstar it replaced.
However, i sodl the trasnmitter nad built a Signal (TI) which is simialr geo, slightly steepr HA and shallower ST, same CS length (short as) and have found it more willing to lift and hop which surprised me as a 29er
Im also not an amazing rider so mileage may vary

Arent stanton switchback and stif morf long and low?

I love Cotic hardtails, BFe or Soul.

The mk1 16.5 Switchback I’ve got is short (~400mm reach) but still pretty low (~35mm BB drop), so not ‘poppy’ as such but they’re still fun enough to ride like a big BMX. I found it worked best with 130mm forks if that helps at all.

Stanton Sherpa has an unsagged bb drop of 40mm. Must be one of the highest around.

Some Stantons reduced and in stock now https://www.stantonbikes.com/shop/48-hour-frames/?utm_source=mailchimp&utm_medium=email&utm_campaign=48+hour+frames+2022

It’s something when you realise you’ve no idea what an acroymn means and everyone else does.
LLS = Long, low, slack?

Been looking at hardtails lately and a couple that have gone to the top of my list are the
Canfield Nimble 9
and the
Production Privee Shan GT

Then I saw the Evans cheapies and ordered a bright yellow Pinnnacle 😛 I’ll probably upgrade sometime

I can see the sense in this thread . I’m still riding a 26” On One 456 Evo ti from 2016 and I can’t imagine how geometry could suit me better.
With the recently added wide and flat 800mm bars and 35mm stem it manuals very easily is also great on the small kickers I ride and is a really poppy fast accelerating trail bike. It’s also good at popping across ditches which we get loads of in our woods. I don’t think I would prefer a long low and slack bike.

I think a lot of that geometry influence came from Competitive Enduro which has a much more downhill bias than fun trail riding.

Update on my original question.

A couple of weeks back I took my Genesis latitude to Swinley forest and struggled of all the down hills. I felt like I had no confidence in the bike and it felt a bit nervous. I didnt enjoy it.

This weekend I got a good deal on a basically new Whyte 905 so I couldnt resist. Its not poppy at all but man does it feel stable and confidence inspriring. Riding the two bikes back to back is funny. My old Genesis feels like a bmx in comparison and manuals and hops so easy. Cant wait to get the Whyte on some steeper terain.