Test it out by doing it as recommended: in whatever pain-free variation you need.
If it helps, cool.
If it doesn't help, and/or makes things worse, have a physio check:
-you hip's ability to internally rotate
-the ability of your tibia to internally rotate (relative to your femur) as you flex your knee
-you foot's ability to pronate. You need foot pronation for dorsiflexion.
All of the above are some things in the kinetic chain that are components of hip/knee/ankle flexion. An ATG split squat may helpl you acheive these things, if you do them properly. However, if you just jam your knee as far past your toes as you can without something listed above happening, you might run into some issues.
Emphases on "may, might, could, maybe...."
Hope it helps.