I am not sure what shading problems you are talking aboutFor instance, there is this:

In context, it’s this area:

Which is actually just this edge that shouldn’t be there giving problems:

remove it and you get:

And then there is:

which causes this:

Which is a lot harder to solve, because you have a 5-sided pole (actually two of them), where you are trying to reduce your geometry…
So, maybe something like this:

Which gives:

Right side ‘fixed’.
Also, you have a lot of 5-sided poles near each other on a curved surface, which creates a lot of shading problems:

Personally I’d first connect everything and then solve the topology/shading. When you do one and then fix the shading and then do the next part, you might end up with new shading artefacts and end up re-doing the topology every time you connect a new piece, if that makes sense…
Maybe sooner use a triangle that is not too stretched, when you can’t avoid it an not use so many 5-sided poles.
These shapes are just really hard, just kep going and you’ll get there.
And even as it is now, it already looks really good!