Hello, just a couple of questions for clarity.
Which apps are you using voice typing in? If it is more than one, are the results the same in all?
How are you turning on or starting voice typing? Some input fields have a mic, and there is a mic on the keyboard, and there may be another way that I'm not thinking of, how do you do it?
Open an input field, touch the field to bring up your keyboard, in the lower left corner there is a keyboard icon, when you touch that what do you have selected?
Are you in ideal environments when you start a voice to text entry? Is it relatively quite, with mostly your voice audible?
Without the answers to these questions just a couple of things come to mind. First it is really odd that in your example you got the words "question mark" and not the symbol. I assume you left that intentionally, thank you for that, this and the short interval for input, makes me think you are not using Google's voice to text and may in fact be using Samsung's offering. It is not automatic and while Samsung's offering is built on the Google model, the experience is much better with Google's offering. Please try the following.
Provide answers to the questions above and let us know what you find and if the instructions were helpful.