This thread below on Google Drive Help Center was closed with a response that you can now block a specific user — which is useless against a horde of bots.
https://support.google.com/drive/thread/58636526/how-to-bloc...
Sending in-product feedback certainly could work because it's more likely to be seen by product management as it continues to roll in.
Support-driven product change requests are well intentioned but generally break down as a process internally. The working knowledge base and incentives are not properly aligned.
If it could work, we would have seen that happening. We have not, so we must assume it can't. Thus, asking to "send feedback in-product" is just a way to waste everyone's time. You avoid the negative stigma that is associated with knowing a problem exists and ignoring it, without having to undertake any concrete action. Corporate spin at it's finest.
That may not work for you if you want shared item notifications, but I already get bombarded by a million different notifications for everything (sometimes I hate the modern world) and I sure as hell don't want shared item notifications - if something is important enough that I should read it, the person who shared it to me will email me about it.