Advice on what should I do in Japan

I'll be graduating from a polytechnic college in my local country next year around april-may. I will have my diploma certificate by then, majoring in multimedia and infocomm security. I was suppose to go to Japan this year may for a Overseas Institutional Placement Programme for 3 months. But it got cancelled due to Covid-19. It has always been my dream to experience how life is like in Japan for a period of time. What I would like to ask is if I should try to apply for a Japan University after graduating? (Maybe TUFS) Or should I just go to a Japanese language school? Or even actually trying to find a place in Japan to work if im able to find a job for me there? I have done several research on these and im considering as my financial capabilities are limited for a Japanese Language School i might be afraid that I could only afford up till 3 months for now. I don't have a course in mind to study to get a degree as my main goal is to experience life in Japan. If I were to go to a Japanese university, the course that i would pick up is Japanese studies. Please let me know if you can advise me anything. Thank you so much!

If you can't afford language school, how can you afford university - tuition, living costs, etc.?

You know yourself best, and it sounds like you've done lots of research already, so choose the path that speaks to you the most. If you can't go straightaway due to financial constraints, spend some time working and saving up first so you can get the most out of your future time in Japan. No one is sure yet when the borders will open, so you may not be able to go early next year anyway!

If you don't know what to study then paying for any course is going to be a waste of money (unless you find something really attractive, in which case go for it). Are you from a country with a 90 day visa waiver? If so then just go as a tourist and rent a monthly apartment. If all you want to do is experience Japan for a short period of time then you don't need to waste money finding an excuse to be there, just go.

I agree with LIZ, if you only want to "experience life in Japan", don't waste time or money in a language school. You can also apply for a Working Holiday Visa, which would allow you to stay there for up to one year, and also work if needed.

I had a friend visit last year for three months on the visa waiver programme as she did a 12-week language course. She got to live in a tiny apartment in Shinjuku and be in Tokyo for a good block of time without the hassle of being a resident. As @Liz says above, you could also come for three months under the waiver programme (if it applies) once travel is allowed in the future.
However, the term "experiencing life in Japan" line is deserving of further comment. What is it you are expecting or wanting to experience? Is it the daily grind of commuting on crowded trains and long office hours/school classes and study before returning to a small apartment at the end of the day, or something else? Living in one place versus another may not be as stimulating or as different than you might think. If you are after a place with different language, then many countries offer that and the differences also relate to what/where you are now.