My extension is losing new users in Safari. Is there any advice on how to fix it?

Hey everyone!
Is there anyone with a Safari extension version? I have big enough traffic(500-1K installs per day) on my extension install page from Safari: https://yousub.info/success.html?utm_source=safari but next I lose more than 90% of the users. Thus, I was wondering if this happened to you as well or if you know why this is the case? The behavior is only in Safari. Maybe is it related to specific site permission in Safari? Thank you for any advice!