I have two Wifi TP-Link access points with the same SSID:
$ sudo /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport -sGoOut
SSID BSSID RSSI CHANNEL HT CC SECURITY (auth/unicast/group)
GoOut e8:48:b8:57:01:61 -74 44 Y -- WPA2(PSK,SAE/AES/AES)
GoOut e8:48:b8:57:01:5f -71 3 Y -- WPA2(PSK,SAE/AES/AES)
GoOut 00:5f:67:9a:e2:64 -47 10 Y -- WPA2(PSK,SAE/AES/AES)
GoOut 00:5f:67:9a:e2:66 -45 48 Y -- WPA2(PSK,SAE/AES/AES)
You can see the :e2:64 is way stronger signal at my current location, however OSX wouldn't switch the network event after minutes:
$ sudo /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport -I
agrCtlRSSI: -75
agrExtRSSI: 0
agrCtlNoise: -92
agrExtNoise: 0
state: running
op mode: station
lastTxRate: 260
maxRate: 144
lastAssocStatus: 0
802.11 auth: open
link auth: wpa3-sae
BSSID: e8:48:b8:57:1:61
SSID: GoOut
MCS: 3
channel: 44,80
You can see it still stays connected to the network with -75 RSSI.
I also tried setting Strongest JoinMode as described in How to enable faster WiFi Roaming with Mac OS X & Airport base stations however that had no effect.