There is not always a well-defined definition of “centering.” Sometimes you want the center of the model to be at 0,0,0. Sometimes you want the model to be sitting exactly on top of the point 0,0,0, like a chair when the ground is at y=0.
Code for computing the bounding box of an object and then moving it around is not too complicated, see https://github.com/donmccurdy/three-gltf-viewer/blob/9ef59abc24fbff84a5f0ce4413ca54a31ef11957/src/viewer.js#L266-L274 for an example.
For a general-purpose tool, I would open the file in Blender, move it, and export the result.
Thanks for the information.
I have already tried the calculation of the movement and rotation myself.
See How to rotate a gltf model in a specific direction - #18 by Heyam
Check it out LoadGLTFmove
Since I’m not interested in modelling myself, I take finished models. When there is time, I have to take a closer look at Blender.