> Last I checked image watermarks were super weak against rotations

Obviously depends on the technique. The old-school popular technique of "slap a signature in the painting" like Dürer's stylized A/D logo is very robust to rotations, but not robust to cropping from the bottom in that case.

> seems to still be the case - but the better methods could cope with cropping way better than these.

It's near impossible to have a watermark technology that's robust to all transformations, at least if you reveal what watermark algorithm you used.

One easy attack that works on most some techniques, would be to just re-encode the content, but writing your own watermark over the original using the same watermarking algorithm.