How to deal with seams between tiled blocks?

Hey community,

in my current hobby project, I tried to arrange different types of blocks dynamically. A ball is moving over those tiled cubes. The problem is, that the balls blobshadow highlights those ugly seams (picture below). The seams also occur on some points of view. The blocks are arranged accurately. I searched for similar problems on the forum, but did not find any direct solution. Do you think those issues are related to wrong UV-Mapping or should I try to work with combineChildren.cs script mentioned in one of the other found topics? I can't find the script in the standard assets, while it's possibly the best solution for deleting those seams. Thanks for your (hopefully) upcoming help ;)