I have this door jam with a shelf support cut into it. I'd really like to make it look better and am wondering if I have to remove it to cut it down or if there's a saw that can just slice off the end while it's in place.

I would have liked to put an angled cut on the ends rather than leaving them square, so they don't jut out like that but not sure it's worth it to take those pieces off now that I've filled the screw holes. I saw a nice miter cut treatment recently!

The other side of the closet's shelf support is flush level with the jam with maybe 1/4" space to the jam, so no beveled end is really needed. No gap to the drywall.

Also have to figure out how to fill the jagged gap between the drywall and the jam. It runs the length.

What do you think?