Use axios proxy trough OpenVPN protected frontend in VueJS - axios

Question

hope you are all good.
I'm facing an issue with my frontend instance.
Actually, we have a frontend hosted and secured by OpenVPN credentials. That means, no one can access it without a connection to our VPN. That configuration works well, but still one issue with axios proxies.
Quick notes:
we are not using server-side rendering
frontend hosted in AWS CloudFront
backend deployed to AWS EC2 instances
This is the current configuration in my nuxtjs frontend nuxt.config.js file:
{
...,
proxy: {
'/api/': {
target: !process.env.FLAVOR
? 'http://localhost:8009'
: (process.env.FLAVOR === 'production'
? 'https://api.domain.tld'
: 'https://' + process.env.FLAVOR + '-api.domain.tld'),
pathRewrite: { '^/api/': '/v1/' }
}
},
...
}
This solution helps me to avoid all environments easily, without setting each URL inside my environment variable in Dockerfile, and also the CORS policy.
In that way, if I check the console inspector and verify the network tab, I got access denied because not connected to the client. How do VPN and proxy really work? Are the requests called client-side or server-side?
Thanks by advance for helping me.