Android as external monitor for Linux, x11vnc speed problem

I managed to find a solution to use my android tablet as an external monitor for linux, like duet or WiredXDisplay on Max or Windows.

for those with Intel there is a great solution called virtscreen. NVIDIA and AMD users need a different solution

adb reverse tcp:5900 tcp:5900
adb shell monkey -p com.iiordanov.freebVNC -c android.intent.category.LAUNCHER 1

xrandr --newmode "1200x1920_60.00"  196.47  1200 1296 1424 1648  1920 1921 1924 1987  -HSync +Vsync

xrandr --addmode DP-1-1 1200x1920_60.00

xrandr --output DP-1-1 --mode 1200x1920_60.00 --right-of HDMI-A-1

x11vnc -rfbauth ~/.vnc/passwd -clip 1200x1920+5760+0

These command worked well and very fast enough.
After some tumbleweed updates, it became unusable slow.

is there a way to get a faster x11vnc again?