I am not a teacher.
Commas are dangerous. They can louse up otherwise good writing faster than anything. Use them sparingly, only when the mechanics of the writing calls for them. None of the commas you propose are good, right or needed.
Beginners are tempted to use commas to create cadence. Use words for that, not punctuation, or else write speeches and give them rather than try to produce prose. Writing is not speaking, and you have to let go of the control you have when you are using your voice and try to create an artificial voice out of letters and spaces. It's like in chess, where you should always move a piece rather than a pawn---use words rather than punctuation.
There are many good primers on punctuation. The Elements of Style will get you on the right track.
Student or Learner