How to exclude a backend route when online

[SteamWind]

Hello, I'm experiencing the same kind of problem as this issue but in my case, I want it to work when the user is online.
I tried the configuration of workbox like this:

            workbox: {
                globPatterns: ["**/*.{js,css,html,svg,png,ico,gif}"],
                cleanupOutdatedCaches: true,
                clientsClaim: true,
                navigateFallbackDenylist: [
                    /^\/mybackend.*/,
                ],
            },

When I put me online, the redirection works for any route but /mybackend, which is expected. When I navigate to /mybackend, I get a no network error, which is expected too.
But in my situation, when the network is on, I'm redirected to the app anyway, even when I navigate to /mybackend.
How to have the same behavior when network is online and being redirected to the real page I want on /mybackend, which is not my vite app?

I'm using vite-plugin-pwa version 0.21.1. I've got a vue app on root but different servers on other routes like /mybackend.