Configure signal strength for Network Manager and APs with the same SSID

In my distro, wpa_supplicant is used by NetworkManager, but it is fully configured via DBus. As a result, I cannot specify the bgscan option as described here: https://wiki.archlinux.org/title/Wpa_supplicant . In other words, I cannot use wpa_supplicant.conf, as it is ignored. However, I need to customize the rules for how the client switches between access points with the same SSID. I assume that switching is currently based on *connection* speed, which is not ideal because it doesn’t reflect the actual speed. I would prefer to use RSSI for this purpose. I have not found any settings in NetworkManager config for connection.