The required process, using one of your network computers, being something similar to:
1) Run the copy/paste application (e.g. Robocopy, AZcopy, OneDrive client, etc.) on the network computer.
2) Open a source folder on One Drive.
3) Open a target folder on Google Drive.
4) Copy a file from the One Drive source folder to the Google Drive target folder using the application software.
5) Limit the transfer speed to 10m.
No disagreement regarding Robocopy or any application per se.
However, why not just limit the network computer's bandwidth via the network router?
References - FYI:
https://www.lifewire.com/limit-bandwidth-on-your-router-4685625
https://www.lifewire.com/what-is-bandwidth-control-2617900
Use networking features to directly configure and manage the required bandwidth limit.
What make and model router is being used? (Or modem/router if combined.)
Also, before doing anything, ensure that you can accurately monitor/measure the bandwidth being used during file transfers.
Otherwise, you will not know if any given application and/or configuration is or is not effective.