I would slice off all those stray paper defects with a razor knife or a sharp drywall knife.
Fill the divots with premixed joint compound.
Will need at least two coats.
Then I would fill the biggest voids in those long cracks with premixed joint compound and let it harden for a few days.
Scrape off everything extra, just leave the big cracks filled up.
If you don’t prefill them, sometimes they will suck in your tape as they dry.
Then scrape off any high spots, then cover the corner gaps with paper tape.
Use mesh on any flat surfaces.
However, if you let the bedding coat dry out at all, paper will bubble up and has to be removed.
If your technique is poky and poor, use mesh tape on corners, but it is hard to make a straight edge, and your drywall knife can cut through the mesh corner, so be careful.
Usually easier for a novice to make one side look good, let dry, then finish other side of the corner.