try to put
powertop --auto-tune
into /etc/rc.local (before 'exit 0'!)
I think the big differentiator is power top actually. When I upgraded to 19.10, I was prompted to check the differences between the old/new versions of the power top config file. The new version had a few more comments and was clearly updated, so I used the new config file during the upgrade process and went through all the options to make sure they made sense for my laptop.
4 years is long enough for lithium batteries to decline pretty noticeably.
Yup, my xps 15 battery of that same vintage had to be replaced at the beginning of the year (under warranty).
Sorry, the MBP was my old work computer. I don't have it anymore. I was referring to its battery performance at the time.
with laptops, it really pays to make sure your kernel as recent as possible