Removing Azure AD Photos

Hi everyone, I'm having some issues and Microsoft support don't seem to be getting anywhere with it -

We had our AD Connect set to sync the ThumbnailPhoto attribute to AAD (unfortunately) which apparently uploaded the images to AAD (where they are not visible for most people, and the majority of the ones who are visible don't error), and now on every AAD export it tries to re-import these images that are too large (despite the AAD photo size requirement being far smaller than AD) - with the error 'ExceededAllowedLength'.

I've gone into the connectors and set it to not sync those attributes either way, as well as setting new sync rules to set those attributes to the recommended 'AuthoritativeNull' set to either update and replace but that still doesn't seem to be doing anything and errors have stayed the same.

There seem to be Get- and Set-AzureADUserThumbnailPhoto cmdlets, but I can't find a way to simply remove them - setting to $null doesn't work.

These sync errors are delaying a new software that relies on successful AAD syncs, are there any suggestions for what I could try next while waiting for Microsoft's response?