That is good for you. My iPhone 6S+ battery drains rapidly and shuts down randomly when battery charge is less than 50% on 13.7.
13.6.1 was much better behaved.
Ugh, sorry. This is why it's so hesitating to update - when I see posts like this. (Is it safe, it is stable??)
Almost feel its a crapshoot now...
Even though it's "unsigned", You can still grab the old 13.6.1 iOS from here. Restore the iPhone.
https://ipsw.me/iPhone8,2 (6S+)
I did update to 13.7. So far so good in the past 2 days...I haven't had heavy use with this so far like I did over the long weekend. Heating issue SEEMS to be a little better, (On 13.6.1 I would have it on my charger and it would feel slightly warm, that particular issue feels like it went away)
Battery life / drain seems about the same for now.