This setting is not just for Steam Remote Play; it also affects other streaming apps. Uncheck it.
Here’s a structured for a product or tool addressing Steam download drops (intermittent speed drops, stalls, or fluctuations). steam download drop
If you open the Steam download page and look at the "Disk" utilization, you will see the truth. When a occurs, watch the "Disk" activity. Does it hit 100% while speed drops to zero? This setting is not just for Steam Remote