See, I think nothing is more important than devotion, hard work, practice and a lot of practice and much more practice of questions.
I am in class 12 and have taken coaching for NEET and AIIMS preparation(in class 11th too) in a what you meant as a “professional” coaching classes.
What I personally feel after an year of coaching that you don’t need it if brilliant enough to understand each and every word ,and its meaning and reference , of NCERT , especially in Biology.
Teachers in coachings help you understand those “andar ki baat” of NCERT.
This reduces a lot of burden and helps to make up time for practicing questions.Moreover, they are always available for solving our doubts.
But, most of the time what we get to hear from our teachers is “ tumhare success mein Kisi bhi teacher ya coaching ka Sirf 20% hi contribution hoga. Baaki saari mehnat tumko khud hi karni hai.”
So if you are good enough to get into the depths of NCERT and manage your time as well, surely you don’t need any coaching.