its also limited by the setting on the host pc

steam -> settings -> remote play -> advanced client options -> bandwidth limit
set it to 50-75mb/s or ulmited for 1080p
or if streaming outside your house or to a non direct connction, then about 75% of the internet upload speed at host location

if using wifi, check the router settings, and disable wifi isolation for the ssid you use, so streaming in your own house/equipment will allow devices to talk directly to each other

set windows network to private not public
and disable any vpn

those will also force remote play to use steams internet relays, and your internet upload+download
instead of direct connection using only lan/wifi bandwidth