Okay. If Electrum cannot detect how many devices are connected to this wallet and when this account was accessed last, then I have nothing to say.
You are fundamentally misunderstanding how bitcoin works.
Electrum does not "connect" to a wallet. Indeed, there are no wallets to connect to at all (outside of centralized exchanges in which someone else is holding your coins for you, but even then you are simply connecting to this third party and not to some wallet on the blockchain). Your wallet is simply a collection of your private keys. Your private keys are used to unlock certain addresses and allow you to move the bitcoin on those addresses. The bitcoin itself is not in your wallet - it is on the blockchain. All you have on your computer is a collection of private keys.
Now, if I've managed to access your seed phrase, then I can regenerate those exact same private keys and have them on my computer. How could your computer possibly know if my computer, or if any other computer in the entire world, also holds those same private keys? Think of it like this: You've created an encrypted file which is storing some sensitive data. You set up an alert on your computer to notify you every time that file is decrypted, so you know if anyone else is opening it. However, I plant some malware on your computer which copies this file and sends it to me. I can now decrypt it and open it on my computer, read all the contents, and your alert system would be none the wiser.
Suppose my wallet is already compromised for whatever reason, but it does not have a balance. The hacker will wait until a new deposit comes up.
Correct. The solution to this is to have good security in the first place, usually by using a hardware wallet or an airgapped device. If you are ever concerned your wallets might be compromised, then set up new secure wallets and transfer all your funds.
If I can check that my wallet was logged in from another device or, say, from a different IP, I simply won't deposit to this wallet, and I will be able to escape the hacker.
As explained, this is not possible because there is no wallet to log in to in the first place. There is simply a collection of private keys stored on your computer.