By default, many consumer and enterprise drivers are set to "Low" or "Medium" aggressiveness to preserve battery life and connection stability. This causes devices to remain connected to an AP with very poor signal (e.g., -85 dBm) rather than roaming to a nearer AP with a strong signal (e.g., -45 dBm). This results in low data rates and high retransmission rates for the entire cell.
Apple does not expose this setting to users. macOS uses a proprietary, adaptive algorithm (AWDL and legacy scans). Generally, Apple clients are "Medium" leaning toward "High" for Apple-certified APs (AirPort, Cisco, Meraki). You cannot change it. roaming aggressiveness wifi
If you take one thing away from this piece, let it be this: If one laptop has its roaming aggressiveness set to "Maximum" in a dense AP environment, it will suffer. Tune your clients, not just your access points. By default, many consumer and enterprise drivers are