need advice for physics compartment

they only increased 1 mark despite challenging for 8 marks. but anyways I've thought kf starting comp preparation from today so i have a few doubts.

1. i saw someone say ki logo ka 12 hours padhne ke baad bhi comp clear nahi hota so i just want to ask is it actually that hard? is it harder to pass compartment than the normal one? and what is the passing ratio?

2. i want to score 50+, is it achievable in 18 days? (I've forgotten most of the syllabus sadly)

3. im thinking of practicing last few years comp/improvement pyqs, what else should i practice from?