Hi,
I installed Metamask extension on another device in my home and did the import using secret recovery phase to login and it asked to create a new password, why new password needed and why cant I use my previous old password?
It's up to you whether you want to use the old password or the new one, but why would you want to use the same password on all devices?
Okay I logged back in and see my settings are not synced and my metamask looks like it has gone back to default settings with all the networks that I originally added on my 1st device that I used 1st time to create the metamask wallet is all gone.
How do I sync my metamask wallets between different devices so metamask settings & networks are synced?
Because that's how metamask is designed. It's a noncustodial wallet, so It's not going to store all your passwords or setting in the cloud so that you can sync them.
Any setting you add manually is locally stored in the computer/device.