You can add RAM with 3600Mhz if you want but the laptop System Memory will still run at 2400Mhz.
PC will always run at the slowest RAM installed in the system.
I would google your laptop's exact Model to find out which RAM is compatible with your laptop which I did and one that came up is from Crucial RAM: https://www.crucial.com/compatible-upgrade-for/asus/tuf-gaming-fx505dt
NOTE: According to Crucial, it seems your laptop original RAM is replaceable and not soldered on. Therefore if you can replace your original Laptop RAM module with a set of 2 Crucial 3200Mhz RAM then you will be able to achieve a higher RAM speed than 2400Mhz.
