Here's an Autohotkey script I made for auto-switching scenes

[chancet]

I think there's addons for OBS that can do this but here's another way using Autohotkey (https://autohotkey.com/download/). Just use this script I made for Autohotkey and set the hotkeys in the settings of OBS to alt+numpad4, alt+numpad5 and alt+numpad6 for each scene. I use this when I'm shooting live music performances to regularly switch between my 3 cameras every 10 and 8 seconds automatically (I show my front camera twice before looping).

Loop
{
Send, !3::Send !{Numpad4}
Sleep, 8000
Send, !3::Send !{Numpad5}
Sleep, 10000
Send, !3::Send !{Numpad4}
Sleep, 8000
Send, !3::Send !{Numpad6}
Sleep, 10000
}
Return