I read this article by Peter Easton about battery management.
It's just confusing at the end whether plugging in all time is a good choice. It would be better if GrapheneOS itself had an Article about Battery Management, it would be more trustworthy.
I have tried to claim warranty for the Anker charger I bought. It has 18 month warranty and it has only been 6 months of using it. I have asked for a refund and so I could buy a Google Charger instead of it, they would respond within 2 days.