@Slepe  The Delay for Failover may be related to the hardware performance of the router itself. On the management page and the related firmware version didn't see any option or note that can improve the delay.

If you want to keep internet online all the time, turn off the Failover and enable the Load Balance may help. This is to make two WANs online.

@John1234 Hello there! Thanks for the answer.

That's unfortunate that there's no way to adjust it. the delay(20s) is consistent, so I was thinking there was a way to adjust it.

Failover is already of and load balancing is already on, it didn't help.

Do you have any idea if other routers have that functionality from tplink? I don't mind buying another if I have to