The problem QoS addresses
When upload or download links are saturated, queues can grow and interactive traffic may wait behind large transfers. Traffic management can reduce that delay by scheduling or shaping flows more deliberately.
It cannot create capacity
If the household requires more sustained bandwidth than the connection can provide, prioritization only decides which traffic receives preference. It does not generate extra Mbps.
Adaptive/automatic QoS
Many consumer routers offer automatic or adaptive QoS. Effectiveness depends on accurate knowledge of the actual WAN rate and the vendor's scheduling implementation.
Test under load
QoS benefits are most visible when the connection is busy. Compare call/game latency or responsiveness while a large upload/download is running rather than judging only an idle speed test.
Networking capabilities vary by hardware, firmware, ISP, country and radio environment. Settings names differ among manufacturers, so use your device's current documentation for product-specific changes.