Why not switch to a turntable from a specialist manufacturer. Project are well known, Rega less so.
The situation described in this post in unique while we have tons of post about many problems with cheap junk belt-dive like Rega and Pro-Ject every week.
Unless there will be clear evidence that it’s a factory defect we can even talk about it, because no one else have such problem with Technics platter.
watch this video:
Mastering the Craftsmanship — Making of New SL-1200