Waiting room

Publicly publishing a Zoom meeting on social media is not recommended for that very reason. If you need to control participants you could restrict meeting participants and webinar attendees to authorized users only, hosts can configure authentication profiles. This feature allows hosts to require participants to sign in to Zoom and even further restrict access to users whose email addresses match a specific domain. Additionally, hosts can add authentication exceptions to allow specific users outside the specified domains to bypass authentication and join the meeting. This can be useful for ensuring that only verified users or users from a particular organization can participate in the meeting or webinar.

You could also make the meeting a paid event to discourage unwanted visitors.

Can't just remove them? You should be able to go to the dots by their name and drop list will show with the option to remove them. Once you remove them they cannot rejoin.