How many sessions are recommended for acne scar treatment?

I heard that scars left behind after acne don't disappear easily, even after a long time. I also heard that the treatment methods differ depending on whether the skin is deeply indented or just has red marks, so I have some questions.

I looked up acne scar treatment methods and found procedures like Fraxel and Subcision, but I'm not sure which types of scars they are suitable for. I'm also wondering if lasers alone can improve uneven skin surfaces.

Does the recommended number of acne scar treatments vary depending on the depth or age of the scar? I would like to know if there is a significant difference in the number of treatments required between shallow scars and deep pitted scars.

I am also curious about how much change I can expect from a single treatment. If multiple treatments are required, I would like to know if sufficient recovery time is needed between sessions and how often they are typically performed.

I heard that the skin may turn red or scabs may form during acne scar treatment. I am worried that the irritation might linger for people with sensitive skin. I would also like to know what precautions I should take to prevent hyperpigmentation after treatment.

Would it be better to accurately identify the type of scar before determining the recommended number of acne scar treatments? Rather than undergoing multiple sessions unconditionally, I would like to establish a treatment plan tailored to my skin condition.

For those of you who have sought counseling for similar concerns, what was the initial explanation you received? Please share any advice you can use as a reference when deciding on the treatment method and frequency.