Don't know how or what your looking for, never used an iphone, but Samsung Good Guardians has a battery health thing in it and other stuff. If you don't have Good Lock that's handy as well. Samsung store.
Settings, battery, click the usage graphic. Figured you already might know that though. For screen on time, pencentage of life daily, 7 days etc.
There are apps on the play store that run in the background and they within I think depends on the app but a couple charge sessions can roughly determine your battery health, I think it's pretty accurate but it's just the downside of having that app run in the background for possibly a couple days but once you find out you can delete them but they are useful for battery info