Actual behavior

I want to put a form outline inside an input group, when i do this the size of the input is reduced, also when the input-group is large the text inside the input is not centered here is the code,

<div class="input-group input-group-lg mb-3">
                <span class="input-group-text" id="basic-addon1">@@</span>
                <div class="form-outline">
                    <input type="text" id="form12" class="form-control" />
                    <label class="form-label" for="form12">Example label</label>
                </div>
            </div>

Expected behavior i want to be able to use an input group with a form outline that is large and looks well

Resources (screenshots, code snippets etc.) i cannot paste image, sorry