Waittt I thought pr requirement is just 2 years study and 2 years work experience, then you calculate points if it’s equal to crs score
No - that's quite how how it works and this doesn't automatically mean you get PR.
First of all, you will be competing against other applicants in the program. This means that IRCC selects the applicants with the highest points and this means there's no guarantee you will be selected. You get more points if you have advanced education. Many people in the pool will have Bachelor and Master's degrees which will get them more points. A number will have PhDs. You will be competing against these people for Canada to select you. You will also need to get at least one year of work experience in a skilled occupation (NOC A, B, or 0) to qualify to apply. With only a two year diploma and no real past work experience, the risk is that you may struggle to find a skilled job and get the required work experience to apply. This will be the risk you're facing. You will certainly find a job. However it may be skill level C or D and this work experience won't qualify for Express Entry.
There have been some low CRS scores recently. However this is due to COVID and changes in how IRCC has done draws this past year. Do not assume this will continue. This will most likely end this year. Scores will most likely go up again. And we've seen many people in the past struggle to convert a study permit and PGWP to PR with lower levels of study. That's your risk.