Unemployment days during OPT/STEM and 60-day grace period impact

Hi everyone, could someone help me understand the rules surrounding unemployment days during your OPT+STEM OPT period and the 60-day grace period. My understanding is that as long as you dont exceed the total 150 days of unemployment throughout the OPT and STEM OPT period, you should be eligible for the 60-day grace period once you reach your end date. The status of employment at the end date does not matter as long as you haven't exceeded the 150 days, right?

Here is the scenario:

Let's say you have 145 days of unemployment days left and have 140 more days until the end of your STEM OPT date. If you quit your job or get laid off today and do not get another job, when the 140th day comes, will you still get the 60 more days of grace period after that?

I have received multiple misinformation from my DSO regarding different immigration scenarios, so I wanted to do my own research before asking them. Any help or sharing of your experience would be helpful. Thank you!