Fusion imports some SVGs with shapes that will not close, so there is no profile to extrude. Drop that file in here and it comes back redrawn as one sketch: no color, nothing crossing anything, every curve on a closed loop, at its real millimeter size. Your file never leaves this device.
Drop your SVG here
and the fixed one downloads by itself
reading the file
Anything narrower than the smallest detail is trace noise rather than art, and is absorbed into whichever shape it borders most. Lower it to keep finer detail; raise it if slivers survive. Changing a setting redraws the file - it will not download a second copy by itself.