IOS pwa start_url doesn't dynamically changes

Question

Well I am working on a pwa (react) project, and came across with a weird bug. I've created a manifest.json initial manifest file and a script where i change the start url and the src of the icons according to the specific user.

Problem is that on the android devices I have the full pwa functionallity, the pwa saves perfectly while on the IOS it doesnt, it opens the start url from the initial manifest.json.

<link crossorigin="use-credentials" id="my-manifest-placeholder" rel="manifest" />
        <script>
            async function setDynamicManifest() {
                const basePath = location.pathname.split('/')[1];
                const manifestTemplateUrl = '/manifest.json';
                const response = await fetch(manifestTemplateUrl);
                let manifest = await response.json();
                manifest.start_url = `${origin}/${basePath}/login`;
                manifest.icons = manifest.icons.map((icon) => ({
                    ...icon,
                    src: `${origin}/${icon.src}`,
                }));
                manifest.screenshots = manifest.screenshots.map((icon) => ({
                    ...icon,
                    src: `${origin}/${icon.src}`,
                }));
                console.log(window.location.origin);
                console.log(manifest);
                const manifestBlob = new Blob([JSON.stringify(manifest)], { type: 'application/json' });
                document.querySelector('#my-manifest-placeholder').setAttribute('href', URL.createObjectURL(manifestBlob));
            }
            setDynamicManifest();
        </script>

There are no errors, the IOS allows me to save to home page the app its just doesnt run the logic from the script. anyone had a similar situation? NOTE: using lighthouse pwa test the code is instalable and truely does, I just need to dynamically change the start_url and src.

Thanks!