At one point I was claimed for the american opportunity tax prior to 2019 when I dropped out. Coming back 2019-2024, completed my.degrre is this tax applicable or reset?

It does not "re-set".    You can use that credit---the AOTC  -- a grand total of four times which will include using it on a parent's return or on your own return, for the years in which you are pursuing a four year degree.