@gorank, I'm tinkering around with my own capture app on iOS and preprocessing on MacOS to learn about the necessary steps. Thanks for the hint on 3D Splat App. Running a test right now. Looks good. Indeed fast and quality is promising.

I've moved on from Brush - on MacOS you have two good and free options: 3D Splat App (in the app store) and Spirula Studio (on github). Both work very well, with more control and usually better & faster results than Brush. For reconstruction I still use Colmap - it still gives the best quality. Try one thing if you haven't: if you're reconstructing in Colmap and telling it to use one shared camera for all images (even if it is, being a single iphone), try setting it to one camera per image. You'll probably need to strip away the exif data so it doesn't pick it up. For iphone, try either radial or opencv model. But somehow it does make a difference when you have one camera per image, I suppose the change in focus length from picture to picture changes the camera model parameters slightly.

True. For detailed shots the phone does indeed a better job. But covering a few 360° spheres with the phone at different locations takes some discipline. Perhaps a combination of the two would solve that. Resolving the poses and undistortion of the panoramic images, as well as figuring out differences in exposure and white balance sounds not easy, though.

I don't think a 360 camera is better. It only makes it much easier, to get all views in no time. But the angular resolution of a 360 camera sucks. You could never capture your bike in that detail with a 360 camera.