Can't change WAN settings on Nest Router

[lobsterboy]

I changed ISP and need to change WAN settings from DHCP to PPPoE. This is impossible!.
I followed the steps and disconnected the main Nest Router from ethernet, disabled mobile data and connected to its wifi with my phone. Google home app failed loading. Restarted the Nest Router, restarted my phone, tried with google home android, tried with google home iOS. nothing works.
Any known way to make it work?

[lobsterboy]

@FiorenzoDV

I saw you fixed it with iphone app. I tried from an iphone and it didn't work for me. I invited the iphone owner as co-admin of my home account but unfortunately it didn't work. Can you please describe how you managed to solve it?

[lobsterboy]

@MichaelP maybe you have an idea?

[MichaelP]

Not really, no. The only thing I can suggest is doing a complete factory reset and then setting it up from scratch as if it was new out of the box. Use the same network name and password so all your clients connect again automatically.