When you provide options.position it will apply an affine transformation to move the data from the local GLTF coordinates to that location in WGS84. It will not do any reprojection of the data. This works well for smaller data sets (such as a scan of a building). If you have a data set the covers a large area (like a 500 km highway), this will result in some noticable differences from the reprojected positions at locations further away from the origin.
Currently we don’t support reprojecting non BIM GLTF data, but this is something that is on our radar.
As a work around, you could try breaking the single large data set up in to several smaller files with different origins to minimize the differences between the affine and reprojected positions