Well, I've managed to do on a different way, thanks a lot for your help. Here is the code:
#import wifisetup
#wifisetup.auto_connect()
import network
from m5stack import *
from m5ui import *
from m5_pin import *
from m5mqtt import M5mqtt
from time import strftime, ticks_ms, ticks_diff, sleep_ms
import utime
import _thread
def connect(ssid,auth,timeout=6000):
    from network import WLAN, STA_IF, AP_IF
    global uplink
    uplink = WLAN(STA_IF)
    uplink.active(True)
    uplink.connect(ssid, auth)
    started= ticks_ms()
    while True:
        if uplink.isconnected():
            return True
        else:
            if ticks_diff(ticks_ms(), started) < timeout:
                sleep_ms(100)
                continue
            else:
                return False 
wlan = network.WLAN(network.AP_IF)
while True: 
  if connect('Wifi1', 'password1'):
    red='Wifi1'
    break
  elif connect('Wifi2', 'password2'):
    red='Wifi2'
    break
  
print('connected to: ',red)
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