Ok 5-23 I decided to have another go at 6.138 and this are my findings in my case:
did the upgrade and then factory reset, after that turn of and unplugged the router and modem and turn off PC
turn on following the procedure posted before and everything seem to be working fine until I activated the DDNS service and the VPN service, that's when it went back to could connect but no internet. I usually configured the VPN to access local network only but for some reason it blocks the whole router internet connectivity, configured to allow local network and internet and voila everything is working fine. another thin worth noting is that under Advanced- Security- schedule for some reason everything is selected to block connection for everyday 24hours I unchecked all of them and so far everything is working flawless
