Here's a gameplay look of how RDR2 runs on a GFMX150 igpu. FPS is low and a lot of texture pop-ins, but it is still playable.
Settings:
Texture - Ultra (game takes time to load upon initial startup, but it gets better after 10mins or so)
All other settings set to Low
1280x720 res
TAA med(to make a little smooth.
Specs:
I7 8550U
16GB Ram
GF MX150