two-factor authentication is not really practical???

As per this article https://support.apple.com/en-in/HT204915

What to remember when you use two-factor authentication

Two-factor authentication significantly improves the security of your Apple ID. After you turn it on, signing into your account will require both your password and access to your trusted devices or trusted phone number. To keep your account as secure as possible and help ensure you never lose access, there are a few simple guidelines you should follow: 

• Remember your Apple ID password.
• Use a device passcode on all your devices.
• Keep your trusted phone number(s) up to date.
• Keep your trusted devices physically secure.

You must at least add two trusted numbers it could be your mobile or a landline number to get verification code if a landline number is used the automated call is received speaking code , but essentially in this case you need the possession of an iPhone , you said you are signing in www.icloud.com with your Apple ID and password , it means a web browser is used ( if 2FA was set on your Mac ) , the verification code can be received by clicking on system preferences > iCloud > account details there is an option of getting a verification code , just click on it to get the code even if your device ( iPhone ) is lost / damaged / turned off .

See these articles https://support.apple.com/en-us/HT205362

https://support.apple.com/en-in/HT203977

To sync iPod and a PC sign in with same Apple ID and password on the same network , whenever you sign in with the credentials to enter www.icloud.com , the first page opens is list of applications displayed with find my iPhone , and not directly find my iPhone image .

Hello MMN101.

Welcome to Apple Support Communities.

If I'm understanding correctly, you have some questions about two factor authentication. I will be glad to assist.

Please see the information below regarding not having a trusted device available when signing in from another device:

Two-factor authentication for Apple ID

"What if I can't access a trusted device or didn't receive a verification code?

If you're signing in and don’t have a trusted device handy that can display verification codes, you can have a code sent to your trusted phone number via text message or an automated phone call instead. Click Didn't Get a Code on the sign in screen and choose to send a code to your trusted phone number. You can also get a code directly from Settings on a trusted device. Learn how to get a verification code.

If you use iOS 11.3 or later on your iPhone, you might not need to enter a verification code. In some cases, your trusted phone number can be automatically verified in the background on your iPhone. It’s one less thing to do, and your account is still protected with two-factor authentication."

Cheers.