I haven't done a direct back-to-back comparison, but I was able to generate 8K, 16K, and 32K textures before upgrading to 2.0 and now it seems like I'm limited to 4k textures. The projects I'm testing now are much smaller with much fewer pictures, but the scene is very different so that might be a factor here.
Has Metashape been altered to use more RAM when generating textures? I'll try to do an A/B test between 1.8 and 2.0 to provide more concrete data. Right now I'm pretty frustrated, so I hope this is a bug and not a new limitation.