Currently, Unity does not directly support UDIM textures. However, you can use a plugin or custom scripts to import UDIM textures. By writing a script, you can divide the UDIM texture into multiple separate textures and apply them to different material balls.
Another approach is to create a special shader that supports UDIM textures. You can write a custom shader that uses scripts to calculate texture coordinates and map them to the corresponding UDIM texture quadrants. This avoids the need to create individual material balls for each quadrant.
Regarding your suggestion of using a separate material ball for each quadrant, it is a feasible method to achieve the effect of UDIM textures. However, it is important to note that this approach may increase rendering batches and resource consumption.