You certainly have a good amount of photos captured, some vertically down from the drone would also assist in the future, maybe in a grid type pattern.
Looking at the source image, I’d suggest the issue you are having is a combination of things.
From the textured render you show, the bits that appear to be failing the most are the flat textureless surfaces. - This is a limitation of photogrammetry and not application specific. (giving the objects texture, stickers or something can help at times) or a laser scanner…
You did the correct thing by getting the whole scene in frame in a 360, this is great for registration.
However the subsequent rotations are hardly any closer, (a limitation due to the wide angle lens I expect)
The full res image you provided actually shows only 1/2 -1/4 of the frame has the data needed. so much of the potential image is discarded.
As a example one area I can see it struggled with where 2 flanges connect with a cross over.
This is what the software actually has to work with, we can see the detail and quality is not present. noise and jpeg artifacts will also be causing problems. You can now understand why it struggles.
From a distance the sample image you uploaded looks fine. Your colour render from a distance doesn’t look too bad either…
It is likely that if you took images closer up of the various parts in addition to the overall scene it would have helped.
This could be done by getting the drone closer, and regular terrestrial images.
Things can be tweaked in software however to help account for such things, I’m not the best person to ask. At a guess try increasing the alignment max features - 80k. set preselector 20k and setting detector sensitivity to ultra. (numbers picked out of the air)
Also you may get better results with the normal detail than high.
To conclude the amount of images you have = good accurate registration, however the lack of effective resolution in the images = poor detail.
Keep us updated.