How to control Wi-Fi and background traffic, read latency under load, and spot bufferbloat.
Keep the conditions comparable
Use a wired connection, stop background downloads, and run three tests. Record median download/upload and loaded latency. Repeat in the evening with the same device and server. A large difference only on Wi-Fi points to the local radio link; rising loaded latency with stable throughput may indicate bufferbloat.
Check it with Net Utils
Use the relevant Net Utils tool and compare the structured output with your expected configuration. Public network data changes, so confirm important conclusions with a repeat test.