We recently got access to unity quality settings through the VRCQualitySettings, and it already exposes the "shadowCascades" setting. Unity also has settings to actually change where those cascades start relative to the shadow distance and these settings are called "shadowCascade2Split" if 2 cascades are enabled and "shadowCascade4Split" for 4 cascades respectively.

I created a world that needs a far shadow distance for things to look good, but all the players are concentrated into a small area around spawn. If I increase the shadow distance, players close to the local user are suddenly not inside the first shadow cascade anymore, creating an ugly and visible boundary (the second cascade already looks low resolution at a large shadow distance). If we had access to the shadow cascade settings, it would be possible to have higher quality shadows close to the local user, while still having shadows at a large distance.