3d nail or a finishing nail of sufficient girth that you cut down.

hot and slow for best layer adhesion. you could run a temp tower to see what looks the best for you. I mostly use the bambu presets because if i start changing things i start finding problems. I’ve done 220/210 and it’s fine. Every machine may see temperature slightly different so it’s up to the end user to do proper tests

The sides nearest the base I’ve seen those artifacts recently. Too harsh of an overhang angle that supports seldom fix unless they are basically fusing with the model and you use a different material as the support. You can also change the print orientation to minimize the overhangs but with PLA+ you don’t wanna deviate too much from the reccomended. With nylon you can do whatever you want because the layer adhesion is great.

There are prints you can use to calibrate the support interface distance and it’s specific to your layer height. They are available in bambu software but I imagine you can use them in orca slicer for your specific printer. You can select each tower with a different distance. It’s not a long print.