Can I get braces again?

I have an one impacted lower wisdom teeth (the other was removed already). I’ve seen multiple dentists (4 opinions), and they all advised against removing them because my jaw is very thin and my mouth is small. They’re concerned about the risk of fracturing my jaw during extraction and since I don’t have any pain or symptoms from them, they recommended to not proceed.

My issue is that I previously had braces, but I stopped wearing my retainers for a long time, and now my teeth are starting to shift. It’s not severe, but it’s becoming noticeable and bothering me.

I have a few questions:

1. Is it possible to get braces again just on the upper teeth if the lower wisdom teeth can’t be removed?
2. If I wanted braces on the lower teeth and an extraction (not necessarily the wisdom teeth) was recommended to make space, would that automatically leave a visible gap? Or would orthodontic treatment typically close that space?

I’m trying to understand whether my impacted wisdom teeth would prevent me from getting braces again, especially on the lower arch.

Thank you!