Hi @emag, welcome to the community.
You could show the spinner in a dbc.Modal()
https://dash-bootstrap-components.opensource.faculty.ai/docs/components/modal/
But I’m pretty sure there is a way to do that via css. There is a very good thread about it which I can’t find right now.
Edit: this is the thread I’m referring to
Googling shows quite some results, for example this one.