Automatic subscription renewal assistance

[Dolphin]

Greetings. I have a website. The concept of the site is as follows: for example, if you want to purchase a subscription for Netflix, whether it's for 3 months or 1 month, it doesn't matter, you can enter the number of months and make the payment with the balance on the site. However, if you have subscribed for x months and need to renew it when the x month period ends, you have to do it manually. I want this to be automatic as well, so that when the x month period ends, it renews using the site balance. However, I don't want to use cron jobs as it seems unnecessary; I'm looking for a different solution. Thanks in advance to those who can help. The site has not been fully launched yet. There are many bugs, but for an example, I'm sharing the link: https://hostgame.biz