How to make Note 8 screen dimmer?
I have an earlier Samsung phone which can use Llama, an automation tool which sets profiles that activate upon entry/exit to known areas, like Wifi seen/not seen. Your phone can most likely use it or a similar automation tool to do the same.

In Llama, I have set up a profile for nighttime (time range), plus my specific area, to lower volume and screen dim. Llama's settings allow screen dimming down to as little as 1% from its selector, with about a dozen settings to choose from.

Disclaimer: I am not the developer of Llama, just a satisifed user for many years.