I found the best way to run an internet speed test (and use the results for better Wi-Fi)

This guide explains how to accurately test home internet speeds using Ookla Speedtest, clarifying key terms (Mbps, latency, jitter, packet loss), outlining preparation steps for reliable results (use Ethernet, close background apps, reboot router), showing how to interpret outcomes for common activities, and recommending practical ways to improve performance (upgrade hardware, firmware updates, manage devices, switch Wi‑Fi bands, contact ISP). It is a general networking how‑to focused on consumer home Wi‑Fi optimization.