What are the services of broadcasting among WhatsApp subscribers?

Question

Computer networks

Hello.
There are several foreign services for sending (broadcasting, informing) messages among WhatsApp subscribers:
https://www.whatsbroadcast.com/
https://atms.at/en
https://swat.io/en
But everyone has one problem , they do not work on the territory of the Russian Federation, in connection with Law N 149 “On Information, Information Technologies and Information Protection”, which obliges site owners to store personal data of Russians on the territory of Russia.
Who knows similar solutions (services) operating in Russia?
Important point! We need a service specifically for broadcasting among subscribers, that is, people themselves must initiate the process of subscribing / unsubscribing from mailing lists.