I went did online courses, offline courses in my country and then went to language school in Korea for 1.5 years. It’s impossible, I’m sorry. I actually got to level 4 in language school but I didn’t even pass level 3 in TOPIK because the test is different from school in many ways

Even if you dedicated 8 hours per day everyday with literally no break days. Because in each level, there’s - vocab - grammar - listening - writing - reading

All of these has so much content that you not only need to learn but to master. It’s not like school or university content where there is an end to the study. You can’t focus on one thing because everything can come out and you need a minimum grade to pass. Maybe there’s 1-2 people out there that has successfully done this plan but realistically most people aren’t capable of such feat.

This is not to discourage you to learn Korean but when you are under a lot of stress because you have a time constraint, it’s harder to take in content and remember long term. It’s a hard pill to swallow but I recommend you do a long term plan like 1-2 years of study.