It´s not possible to use Material Parameter Collections with bigger worlds than 21x21km (still same like before)…
Tested in 5.5 with my old project and a new one, added trees with fading out leaves from camera to player location and used WPO to reduce landscape grass height near the character ^^
When do you want to add this or is there anything new, which has replaced MPCs and I didn´t see in the last 4 years in ue5?