Which? recently reported that they had conducted a review of the most popular wireless cameras, and that a number fell short in terms of security and privacy.
They cited the TP-Link Tapo C200 camera, where they found a vulnerability if an attacker was connected to the same network. Which? reported this to TP-Link and, since the firmware could be remotely updated, TP-Link have issued a fix which is available to everyone when they use the app and click to update the firmware.
So the moral of this story is that you should choose wireless cameras (and other IoT devices) that can have their firmware remotely updated.