Hmm, I’m finding this to actually.
Things are less spreadable now than in past versions of AR.
I tried this little test;
Starting in AR5. Default opening canvas.
Oil Brush settings set to default, size 100%
After Painting, layer duplicated. One for use in AR5 one for AR6.
Knife set to defaults, size 50%, then Pressure set to 100%
To avoid any pressure info from my tablet affecting things I then used a mouse to spread the paint as far as it would go in one stroke.
Saved, Opened next in AR6 and repeated the knife strokes with the same tool settings.
AR6 is spreading the paint less.