what is the url scheme safari ?
I tried this way:
window.open(`com-apple-mobilesafari-tab:https://mysite.ao}/?a`, '_blank', 'popup');
url scheme safari
Try x-safari-https:, as in:
x-safari-https://christiantietze.de/posts/2023/05/safari-for-mac-url-scheme
Which incidentally is a blog post about this :)