So, got the 2.8 fixed.

What mode then would be preferable to shoot in? App? Shutter? Auto? Manual?

Shooting indoor volleyball, basketball.

So, got the 2.8 fixed.

Hmm... new lens, got one repaired - not sure what you mean here.

If you're shooting indoor sports then the light level shouldn't change (if there are windows, then maybe one side is a little brighter than the other but let's assume this isn't the case). If you use any sort of automatic setting then the meter may give you different results based on how the scene looks to the camera - remember that the camera sees everything as 18% grey. So if you're shooting a team with white uniforms, then one with dark colored uniforms you'll get different exposure readings in the same light.

Personally I'd go with manual exposure, pick the slowest shutter speed I could get away with to stop action, then aperture I need to use that shutter speed. ISO400 or 800 would be good ones to start with, but any of these settings will take some experimenting to get exactly the results you want.

Sorry. I guess I was cryptic in my description.

I just a new 2.8 fixed aperture zoom lense. So, the aperture does not change throughout the focal range.

So....given I shoot indoors, volleyball/basketball, do I shoot in "aperture preferred" mode, Shutter (speed) preferred or priority mode, automatic or manual modes?

OK - makes sense now. I'd still shoot in manual mode and actually even moreso because you wouldn't have to worry about your aperture changing as you zoom (as you would with a variable aperture zoom).

IOW, for example if you had something like a 70-300 f4-5.6 you'd be properly exposed at the 70mm end of the zoom but one stop underexposed at the 300mm end. You'd also have a tough time indoors with an f5.6 because of the low light level.

So, got the 2.8 fixed.

What mode then would be preferable to shoot in? App? Shutter? Auto? Manual?

Shooting indoor volleyball, basketball.

I shoot indoor basketball as well. Last year I used my 28-70mm f2.8 and this year I'm using my 80-200mm f2.8. I shoot in Aperture Priority mode, usually at f4, unless a really sunny day, then I'll shoot at f5.6 or so. This is with a F5, Superia Xtra 400 film and an SB-28.