I would lean towards the safe side and regenerate another secret key for each account involved since I doubt your data will be deleted on their servers.
It will be better for people to change their secret codes entirely just as you said. It is a good advice.
That's bad news, I have a lot of accounts and trading platforms that connect to the google 2FA app, why did they decide that? Or what is the wisdom of that, given that you can extract the private key and save it yourself, why do they need to keep it in a server or cloud.
You mean to extract the secret code? That is true. Also that on every site or wallet like Electrum, before you can use the OTP, the secret code would first be generated and you can do the manual backup.
If in case someone uses Electrum as a Bitcoin wallet on android and chooses the address Wallet with two-factor authentication, then he installs Electrum windows Portable version on the computer by choosing to enter the seed that was obtained when making it on android and entering the google authenticator code, say someone that's me. Can it have a negative effect on me like this case?
Let me tell you the negative effect.
Do you have chrome on your Android phone? Click on the dots at the upper right corner and click on settings. You will see password manager.
Assuming you have your 2FA on another device because you think it is safe like that. Some people that are using online accounts like custodial wallet, exchanges or anything that has to do with 2FA like Electrum 2FA wallet can be affected because what is called two factor authenticator is no more two factor authenticator if it is linked to the email on the phone. By just downloadimg the app on the device and use the email with it, you will see the OTPs generating. Some people can be very careless and synchronize their username, password and 2FA. What else do hackers need to hack successfully? Nothing. Those three are enough to steal from people.
Do not save your username, password and 2FA codes on Google cloud, it is very dangerous.