How can I create a shortcut to bypass VPN apps for coexistence issues on iOS 18.5?

Why are you using a VPN at all?

Unless you're using it to connect to a secure network like your employer or school to access resources on that network, it serves almost no legitimate process.

Using a VPN to access the Internet does absolutely nothing to protect your privacy or secure your data. Exactly the opposite, in fact.

Using it to bypass geo-restrictions on content isn't entirely legal.

The use of the VPN is your only problem there. Some people think they are necessary for security, but that is just a marketing ploy.

• https://gist.github.com/joepie91/5a9909939e6ce7d09e29
• https://overengineer.dev/blog/2019/04/08/very-precarious-narrative/

I assume you use case is not for "tunneling" into employer servers or school network.

See Is a VPN necessary? - Apple Community