I was also looking for this information once and found a brief explanation in the RoboForex help section. It turns out there’s no limit on the number of investors—any number of investors can follow a single trader. It’s convenient to get the answer directly from an official source rather than from someone’s assumptions.

Here’s the link https://roboforex.com/help/faq/copy-trading-traders/how-many-investors-can-subscribe-to-a-trader-at-the-same-time/