[kobotouch2711]

To whom it may concern: I tried a lot and it seems, that the Kobo has problems with its "sleep" function (does not wake up until manually hitting the home button), so I created a delay_function simply by counting. Just to be sure, I encapsulate the other functions by a timeout.
Wifi is lost 10-30 times a day, but the current script detects a missing Wifi connection and tries to reconnect.
So far, it has been running for the last 3 days without major issues (so still not perfectly tested, but looks quite promising so far)

# network details
LOG_FILE="/wifijob.log"
log_message() {
     local MESSAGE="$@"
      echo "$(date +"%Y-%m-%d %H:%M:%S") : $MESSAGE" >> "$LOG_FILE"
 }

INTERFACE="wlan0"
WIFI_SSID="MYWIFI"
WIFI_PASSWORD="MYWIFIPASSWORD"

# The IP address to ping
HOST="192.168.0.1"

delay_function() {
  local count=0
  local delay=$1  # Number of seconds to wait
  local start_time=$(date +%s)  

  while [ $(( $(date +%s) - start_time )) -lt $delay ]; do
    count=$((count + 1))
  done

  echo "Waited for $delay seconds by counting to $count."
}

# Function to reconnect to Wi-Fi
reconnect_wifi() {
log_message " #################      Host is not reachable. Reconnecting to WiFi"
timeout 2 echo " ################# Host $HOST is not reachable. Reconnecting to Wi-Fi..."
timeout 60 ifconfig $INTERFACE down
log_message "Ifconfig down. Now sleep for 10s"
timeout 2 echo "Ifconfig down. Now sleep for 10s"
delay_function 10;

timeout 60 ifconfig $INTERFACE up
log_message "Ifconfig up. Now sleep for 10s"
timeout 2 echo "Ifconfig up. Now sleep for 10s"
delay_function 10;

timeout 60 wpa_cli reassociate
    log_message "Wifi hopefully reassociated. Sleep for 30s, check ping and re-enter loop."
    timeout 2 echo "Wifi hopefully reassociated. Sleep for 30s, check ping and re-enter loop"

    status=$(wpa_cli status)
    timeout 2 echo "Current Wi-Fi status: $status"
    log_message "Current Wi-Fi status: $status"
delay_function 30;


timeout 60 wpa_cli reconfigure
    log_message "Wifi hopefully reconfigured. Sleep for 30s, check ping and re-enter loop."
    timeout 2 echo "Wifi hopefully reconfigured. Sleep for 30s, check ping and re-enter loop"

    status=$(wpa_cli status)
    timeout 2 echo "Current Wi-Fi status: $status"
    log_message "Current Wi-Fi status: $status"
delay_function 30;

timeout 10 ping -c 1 $HOST > /dev/null 2>&1
# Check and log the ping result
if [ $? -ne 0 ]; then
    log_message "Ping is still negative :( Now trying to reconnect."
    timeout 2 echo "Ping is still negative :( Now trying to reconnect."

        timeout 60 wpa_cli disconnect # Remove all known networks
        delay_function 5;
        ##timeout 60 wpa_cli remove_network all
        ##timeout 60 wpa_cli save_config
        networks=$(wpa_cli list_networks | grep -v "network id" | wc -l)
        if [ "$networks" -eq 0 ]; then
            timeout 2 echo "No known networks found. Adding new network..."
            log_message "No known networks found. Adding new network..."
            NETWORK_ID=$(wpa_cli add_network)
            timeout 60 wpa_cli set_network $NETWORK_ID ssid "\"$WIFI_SSID\""
            timeout 60 wpa_cli set_network $NETWORK_ID psk "\"$WIFI_PASSWORD\""
            timeout 60 wpa_cli enable_network $NETWORK_ID
            timeout 60 wpa_cli save_config
            timeout 2 echo "Network added with SSID: $WIFI_SSID"
            log_message "Network added with SSID: $WIFI_SSID"
        else
            timeout 2 echo "Known networks already configured. No action needed."
            log_message "Known networks already configured. No action needed."
        fi
        # Reconnect to the new network
        timeout 60 wpa_cli reconnect


    log_message "Wifi hopefully reconnected. Sleep for 30s, check ping and re-enter loop."
    timeout 2 echo "Wifi hopefully reconnected. Sleep for 30s, check ping and re-enter loop"

    delay_function 30;
        status=$(wpa_cli status)
    timeout 2 echo "Current Wi-Fi status: $status"
    log_message "Current Wi-Fi status: $status"

fi

}

while true; do
    # Ping the host
    timeout 10 ping -c 1 $HOST > /dev/null 2>&1
    # Check the ping result
    if [ $? -ne 0 ]; then
        reconnect_wifi
    else
        timeout 2 echo "Host $HOST is reachable."
        #log_message "Host $HOST is reachable."
    fi

    delay_function 10
done