Since nobody cares about the reply from Samsung staff, I will answer by myself.
- What is the maximal supported ouput resolution in DeX mode for DeX station 2018?
2960x1440
- What is the maximal supported ouput resolution for DeX station 2018 when I am mirrowing the screen from my Note 9?
Native of your TV, see detail down below.
- What is the maximal supported ouput resolution in DeX mode for 3rd party USB-C to HDMI converters?
FullHD: 1980x1080
- What is the maximal supported ouput resolution for 3rd party USB-C to HDMI converters when I am mirrowing the screen from my Note 9?
Native for TV, so it could be 4K but HDR content is lost, quality also. The output signal is probably upmixed from FullHD output from the Note 9. I've tested on YT with 4K HDR video. Mirroring produce the output with less details and no HDR information.
