Is it worth it to host a server in the office?

Question

Server equipment

Good day, there is a corporate messenger, approximate tasks:
The number of users is ≈ 10,000 people
The ability to exchange both data files (csv, excel, docx, txt, etc.)
The ability to exchange video and audio recordings, as well as (important!) the ability to exchange photos without quality reduction, that is, there is a full hd or ultra hd photo, and it should be saved as such.
Advise whether it is worth installing a server for such a messenger in the office, and if so, how much memory for such a task may be required and what components to choose for the server

Answer 1

First, it is worth calculating how wide the channel will be required in order to provide everyone at the same time with the ability to transfer such files at the peak.
Then shake your head and cut your wishlist. And count again.
And again shake your head and cut back. And count again.
...
And so on until you come to reality, which is a very harsh thing. Or I didn’t understand something, and 10 thousand people. - this is not a simultaneous number of users, but in general their number (for calculating the store, for example)? Then you need to set the number of simultaneous connections - and still calculate the required channel width. Because first of all, everything will rest against this (unless, of course, this is a server for data exchange within the office :) )

Answer 2

Will there be connections from outside? Will they give you a 10GB channel to the office?)
What messenger? How long should it be stored?