As far as I know - no!

I can imagine that you will get such information with SOAP. But you need to create an app.

On the other side I think good, old Formativ can solve this too. I doubt that there is a final solution - so you have to write new code too.

Oh, wait there is Mailbox Management. But this tool only delivers items per folder but no size information (if I am right).

One 'trick' I use all the time is a Search folder for all messages over a given size,  since most people end up with some very large attachments somewhere in there that  can often easily be cleared out.

Happens so often, I wrote up about it ages ago at  https://www.konecnyad.ca/andyk/bigmail.htm

You can also find out who has what,  with a set of tools I wrote about at https://www.konecnyconsulting.ca/gw/gwbig.html   Then you could ask specific users why they have that 50MB plus message by message name from Step3