I was just wondering what the easiest category for a new Speedrunner

i would probably say Glitchless that way you can learn all the ins & outs of the game.

It depends on the route you choose to run! I would say be creative if you are new make your own route that is based off of someone elses that is currently speedrunning but "dumb it down" a little or add longer routes then gradually work towards adjusting that route closer to the most optimal route if you want to, or dont and just have fun! Up to you at the end of the day really