Am I doing this correct?

If you're intending to hold your weight steady, yes, averaging close to maintenance calories would be correct. Keep in mind that it's not some calculator or fitness tracker that tells you what maintenance calorie level is. Those are just starting estimates, basically the average for demographically similar people. The 4-6 week average trend of your bodyweight (whole menstrual cycles for those who have them) tells you what your actual personal maintenance calories are.

Besides protein, fiber and fats, personally I also want to eat plenty of varied, colorful veggies and fruits for micronutrients and varied fiber. People with some other eating styles would disagree. I also want some probiotic foods, like live-culture yogurt/kefir and such, or unpasteurized saurkraut/kim chi, maybe raw vinegar, and that sort of thing. Again, some people would disagree.

In one sense, I feel like it's always possible to fine-tune nutrition in a more positive direction, but how far to take that is quite individual. The basics - the things you're doing - achieve the majority of the benefits. with further details giving diminishing returns comparatively. For some, obsession becomes a risk, and compulsive or obsessive pursuit of dietary perfection is technically an eating disorder (orthorexia). Finding the right personal balance is good for physical and mental health.

You might want to ask about your workout program over in the Fitness and Exercise or Gaining Weight and Bodybuilding area.

I know more about cardio, since I've done a cardiovascularly intensive sport for a couple of decades. Walking is fine for cardio. After you have a good endurance base from that, there might be additional benefits from mixing in something more intense once or twice a week . . . but here, too, the basics deliver the majority of the benefits and walking is good for that as long as you're enjoying it.

Generically speaking, for strength exercise failure is probably a bit far: Last rep or two of final set very challenging, but still capable of good form might be a better intention. Full body 5 days in a row is also possibly not ideal, since recovery is where the magic - rebuilding the body better - happens. If a beginner as you say, 3 days full body, with a recovery day between each, might give better results. There are splits that can be used over 5 days while allowing for recovery, but they may be more suitable for intermediates. Details matter, and I'm no expert, so those are generalities.

Best wishes!