RankMath Pro Unlimited personal websites Issue

Hi
could you please explain the main difference between agency and pro packages?
In pro it supports Unlimited personal websites.
Can someone buy Pro plan for 59 dollars and sell to their customers?

In turkey everyone sell pro 1 year license for 3-4 dollars – 76 turkish liras
https://www.r10.net/hesap-lisans-alisverisi/3182786-9989-seo-lisans-9989-tum-tema-ve-eklentiler-wp-rocket-perfmatters-wp-automatic-rank-math-kadence-generatepress-128126-a.html

I don’t think they pay for agency plans.
I think they buy pro plan and they install plugin and adds customer’s web sites as a personal web site
Is this possible?
I think they login customer’s web site and install plugin and login with their email account.
I think alot of person earns money from this bug. I think therre must be a limit.

If someone buys Agency plan, how can they install plugins to their customers? Is the process is same as on pro plan? How do you know sites are client websites or personal web sites?

Please reply me soon about on this topic

Thanks