Canon 5D MkIV - Live View behavior and time out?

I am somewhat new to studio photography with C1 (just attempted my first shoot today) and have not found an answer online to a couple issues I am running into. Hoping some studio photographer here can shed some light?

My set-up: Canon 5D MkIV, Several Paul Buff Einsteins with their HUB trigger on camera hot shoe controlled via their app on my iPad (all lights and their trigger are working perfectly), most recent version of Capture One on 16" MacBook Pro M1, TetherTool tethering cable, camera set to auto power off at 2 minutes.

Settings: Manual Mode, f16, 1/200, ISO 100

I have 2 questions, both relating to Live View behavior:

1) I notice that when tethered to C1, if I activate Live View from C1 that the screen on the camera no longer displays a Live View image. This is not a problem, just wondered if that is normal behavior for C1 to completely take over the Live View function?

2) This one really has be scratching my head as I see lots of tutorials online where photographers are using Live View in C1 to arrange products on tables to set a product scene with just their modeling lights on and similar camera settings, but this is not working for me? When I switch on Live View (with my settings above), I just see a black image in Live View and it powers off after 15 seconds? I would expect a black frame with those settings when firing strobes, but in Live View? I finally tried changing my shutter speed to 4-seconds and the Live View barely displays an image, but it does not time out at 15 seconds. I don't see ANY of the studio tutorials where they have to change their camera settings to get Live View to display an image with just their modeling lights on (even though it is a low quality image, the exposure is good enough for positioning the subject). I am sure I am doing something wrong, but I am at a loss. I got through my first shoot, but had give up completely on Live View which I was counting on. Any direction greatly appreciated!