Hi @Jon
vor this display you need this entries in userconfig.txt
max_framebuffer_height=1920
config_hdmi_boost=10
hdmi_group=2
hdmi_mode=87
hdmi_timings=1080 1 26 4 50 1920 1 8 2 6 0 0 0 60 0 135580000 3
hdmi_drive=1
hdmi_blanking=1
important for the working screensaver is hdmi_blanking=1
for a no blank screensaver you can look this, I have create this for exact this AMOLED display :
PeppyMeter can run with random screensaver, to prevent the burnin effect