In ASUS routers power button flashing is NOT a good indicator of going recovery mode

DON'T TRUST POWER LED FLASHING OR NOT. It's not a good indicator, making you believe that router is bricked, whereas it's not. Because I had it, I recovered 2 routers with this alternative method: ASUS RT-N18U and Asus DSL-AC68U.

Instead do this, with a Linux pc preferably, assuming you've done everything in the wiki beforehand. In one terminal do this before even powering up the router:

ping -c 10000

It will keep saying unreachable bla bla. Ok, Do the procedure aforementioned in the wiki again, see if something changes on the pinging terminal. When it succeeds sending packages, it's ok. Now it's in recovery mode. If it gives some miliseconds data, it works. Now do the atftp then put firmware.trx, or do what recovery tool you're doing.