Sharing unique credentials is a clear insider threat warning sign because it violates access control policies and can lead to unauthorized access using legitimate accounts.

A VPN establishes an encrypted tunnel over the Internet (or other untrusted networks), securely linking two separate corporate networks so they can communicate as if on a private network.

A Virtual Private Network (VPN) is the best solution to allow remote employees secure access to company resources without interception concerns. A VPN establishes an encrypted tunnel over the internet, ensuring that data transferred between remote employees and the company is secure from eavesdropping.
Proxy server helps with web content filtering and anonymization but does not provide encrypted access.
NGFW (Next-Generation Firewall) enhances security but is not the primary tool for enabling remote access.
Security zone is a network segmentation technique but does not provide remote access capabilities.

IP geolocation allows you to identify the geographical location of an IP address, enabling you to block or limit access from high-risk regions. By using IP geolocation, you can restrict or monitor traffic coming from certain geographic areas that are known to be sources of frequent cyberattacks. This is an effective way to mitigate risks associated with unwanted or malicious traffic from those regions.