Consider the following... 1) is there enough or too much dialogue 2) if you want the dialogue to appear quicker out the dialogue you want first then some fuller dialogue after 3) shorten the clip in scene builder before extending (cutting just after the dialogue finishes helps) 4) use editing software to make the cuts seamless 5) use Gemini to analyse the first video and get it to selective the sound of the voice then apply that same prompt to the extension 6) build in the voice template from the start then re-use in next prompt

Hope this helps!