Couple of questions of a newbie

First, something about myself: I’m 27 years old, weigh around 65 kg, and have a lean body with a bit of belly fat. I used to go to the gym on and off for about a year (around 2 years ago), and I’ve started again recently — it’s been 2 months now. Currently, I’m following a PPL split:

Workout routine:

Day 1 & 4: Chest, Triceps

Day 2 & 5: Back, Biceps

Day 3: Legs, Shoulders

Day 6: Shoulders + Functional training

Day 7: Rest

Now, my questions:

1. My current protein intake is around 65g per day. Is that okay, or should I increase it? If yes, can you recommend a good whey protein powder brand?

2. Should I take creatine? Also, what exactly does creatine do?

3. How do I know if I’m making progress in my back? I can see and feel improvements in other muscles, but not in my back — is there a way to check progress there?

4. How can I reduce belly fat? I know spot reduction isn’t possible, but it feels like that’s the only place I have fat 😅

5. Is there anything specific I should eat or take care of while going to the gym?