How to balance the number of hosts on prometheus slaves?

Question

Monitoring

The task is to set up monitoring for > 1000 servers using Prometheus. One does not cope, so we decided to raise several prometheus so that each monitors its own group of hosts (example 5 prometheus each monitors 200 hosts).
It would be possible to hard-code in the configs of each prometheus which hosts it should monitor. But the problem is that the list of hosts is not static - some hosts are removed and some are added.
In order not to manually run through the prometheus configs, we decided to write our own application that will receive API requests to remove / add a host and add or remove it from the config.
Is there a ready-made solution for this or will I have to write my own bike?