That snowball effect with interest is real and stressful, but here's what nobody tells you: if the bank won't negotiate it's because you haven't given them a reason to! You need to call with a concrete proposal, like "I can pay 300,000 a month for 12 months" and if that's impossible, then you ask for a longer plan or an interest rate reduction, but you've got to sound like someone who's actually going to follow through.
What changes everything is stopping the minimum payment because that's literally throwing money at the bank while the interest keeps eating everything! I've seen people negotiate directly and end up with a lower rate or a temporary interest freeze, but nothing happens if you don't call.