If we extract the first molar (#6 marked with red), will the next molars (#7 & #8) move to the the space of first molar? (photo)

I have a root canal (#6 marked red), redone 6 months ago. Dentist suggests redoing, then put a crown, then remove third molar (#8 red). But I want to remove the root canal & drag tooth #7 and #8 in its place. Is it better to remove the root canal or #8? If Root canal is extracted, will #7 and #8 replace its space? PS: At 13yo, I had an extraction of first molar (#6 marked blue). In a few months the other molars (#7 & #8 blue) replaced the empty space on their own. I am 28 years old female now!