@Zion0131 You are correct. The 5-year rule never resets, so after you use it you cannot exclude days anymore. I am on a similar situation as you, and I filed as a resident this year. I was J-1 in 2012, then F-1 in 2016-2019. In 2020, since days couldn't be excluded anymore, I passed the substantial presence test.
There is a lot of confusing advice in this forum. You can also go to the Sprintax website and start filling out your tax return. The first step is the substantial presence test. You will enter all your entry and exit dates (and associated statuses) into the US. The test will tell you if you are a resident or not.
