Video camera phone apps
Typically to avoid visual artifacts caused by CRT scan-rates you can adjust the Aperture/Shutter Speed and ISO until the effect goes away. (Try double the refresh rate, aka 1/60) Some apps that support this level of control are:
https://www.opencamera.org.uk/ https://www.filmicpro.com/ ProCam X (HD Camera Pro) Black Magic
Blackmagic Camera on the App Store Blackmagic Camera - Apps on Google Play
ProMovie Recorder (by Panda Apps) DSLR Camera (by Fulvio Scichilone) ManualShot
https://apps.apple.com/app/id891992855
Intro: Capture, Upscaling, Downscaling, Video mixers, including Analog, Digital and Mixed.