The good way is to use Tor, I understand that but I can see that some people use their internet service provider IP directly for their nodes. Assuming if someone uses IP address instead of using Tor, what information can be leaked to the internet service provider?
This is what I am thinking too, thank you for the information.
Linking the wallet address to the user's location is only 100% possible if the user is using a centralized system where their login location can be detected.
I accept this also. It is also possible if using a self-custodial wallet that depends on central servers, the central servers can know your bitcoin addresses and IP address which they use to seek for the person that is using the IP address from the internet service provider. If the internet service provider give them the information needed, they can know the person, but this is still better than using a custodial wallet which is centralized.