trata de actualizarlo a la última versión de Android, si no está disponible por tu operadora trata de usar odin, nougat funciona de maravilla en mi s6 edge+, no tengo quejas.

it's probably because you have it set up to do so, I believe there's an option in the accessibility menu on setting.

I pushed nougat to my s6 edge+ a month ago, Wi-Fi works great as well as 4g, try to free up some space since nougat is larger than marshmallow, and make sure power saving is not on, it can cause performance issues

I bought and international s6+ and it came with marshmallow, decent performance and battery life. A month ago I pushed nougat to it, and believe me, I don't regret it at all, amazing performance, battery life exceeds expectations, great interface and...