Hi openmindedcomedy,
The Stage object (if you have more than one) that is on top of the Object Manager is the one that is used.
The camera that is inside of the camera field will be used.
Transitions are not available to my knowledge. There is, however, the camera transition that can be switched off in the Preferences> Navigation.
I have that off all the time, as it confuses me more than it has ever helped: Is that motion from my animation or from this transition effect? Not my cup of tea at all, to say it politely.
If you need to blend among many cameras, use the Camera Morph.
https://help.maxon.net/c4d/s24/en-us/Default.htm#html/TMORPHCAM-ID_TAGPROPERTIES.html#TMORPHCAM_LIST_MODE
It is only available after you have selected several cameras.
All the best