Android is software ---- the operating system which is written by Google. Who made the phone? I expect Samsung.
Here is a link that has what I think is a CYA comment.
https://www.samsung.com/sa_en/support/mobile-devices/is-the-…
As far as I know all cell phones have lithium ion batteries and these do not have overcharging issues like lead-acid batteries. Over the long haul indeed the maximum usage time does decrease, but not just going dead as far as I know.
If you want more clarity on the potential issues with 7/24 connection to a charger, I suggest you read the owner manual. I just don’t see how a cell phone could need people to remove the charger when the battery is full - it is so common for people to leave it plugged in all night - way beyond the time needed to fully charge.
One thing that can damage cell phone batteries is using 3rd party chargers. Not all 3rd party chargers, but some. I have Apple iPhones. I know with more than a few 3rd party iPhone chargers (particularly the lowest price options) lack the electronics apple uses to protect the phone.