@rail TBF depending on the exact fibre equipment and standards used , it is actually a technical limitation on the upload side afaik. Especially on the 2Gbps setups with passive optical splitters. but even to some extent the 8Gbps, as the performance and power of the fibre SFP module used impacts it. They tend not emit with as much power as they receive.

Not allowing you to provide your own ONT tho is a problem of its own