Which transmission 6spd, 8spd, or 10spd?

[EngineNoO9]

So I’ve been a life long GM owner and do as much maintenance as I can myself. We currently own my old 2007 Avalanche with 240k on it and a newer 2022 suburban with the 3.0l diesel. Looking to get myself a new to me vehicle and I was originally eyeballing a a 2018-2020 GMC Denali to get the 10 spd but some friends of ours just fried their 2018 Denali’s 10 spd for a rather spicy repair bill.  
 

So now I’m kicking around maybe going with a Tahoe or non Denali maybe a little older with the 5.3l and finding a 6 spd and getting the converter preemptively swapped out (we had a 2013 suburban that the converter went out on and fried the trans at like 120k so very familiar with that). Haven’t seen a lot on the 8 spd other than removing the coolant bypass helps…. So for someone using this as a backup family vehicle and commuting to work, what would be the thoughts on which transmission would you recommend?

 

For the record we’ve had a few hiccups on our 2022 10 spd which makes me nervous. Only saving grace there is it’s still under warranty for now. And I don’t care much for gas mileage improvement on a 10 spd if that’s the only upside. I’ll immediately disable AFM/DFM on whatever I get too. 

[Chalie M]

WOW.., you got my attention have a new to me (bought used 6yrs.ago with 5K on the clock) 2019 yukon denali currently at 25K, thinking about performing a trans service? What specifically happened to your friends Trans.???

Thanks