An inexpensive and easily transported solution to single flash portrait photography using a large modifier is seen in this video.
https://www.youtube.com/watch?v=nuoc53wcnbc
I like this type of umbrella because light is not bouncing all over the place as it does with reflector umbrellas that do not have the white baffle or especially with shoot through umbrellas...
However, outdoors I like shoot through umbrellas as an inexpensive and easily set up modifier...
There us a limit to the size of the umbrella used and that limit might be the capability of the flash to fill the umbrella. As an example, I don't think that a hotshoe flash will fill a 60-inch diameter umbrella... I often use that size umbrella when shooting with the larger Godox TTL 360 flash unit which has considerably more output than the typical hotshoe flash. A 48 inch umbrella would be fine for a standard hotshoe flash...
I have a modified flash bracket which can hold my flash 24 inches above the camera and which enables me to fire the flash away from the subject into a 24 inch umbrella reflecting back to the subjects face... Using this rig and a hand held reflector from below the subject's face will give pretty nice butterfly lighting...