The author of this article uses various methods to find hidden cameras in a hotel/AirBnB rooms and tests the effectiveness. Methods used:

• Naked eye: 1 of 27
• Mobile phone app: 3 of 27
• RF detector: 0 of 27
• Cheap $50 lens detector: 2 of 27
• Advanced $400 lens detector: 11 of 27

In short, they were all not very good and techniques and searching styles mattered.

Article:

• https://www.cnbc.com/2024/01/22/how-to-find-a-hidden-camera-in-a-hotel-room-or-house-we-tested-5-ways-.html