Thank you very much for such a detailed answer!
That's not how the calculations work.
Did the rules change on that? It looks like you are correct however I very vividly remember the rules being different. When I first applied for presettled status I watched multiple videos that explained the topic and they all said that you can be absent for up to 180 days in each of 5 years (not in any 12 month window). For example this video https://youtu.be/ISc2ZQ9hFac?t=146 (timestamp 2:26 - 2:58).
To be certain, did you make any preliminary trips to the UK at some point during the 12 months between August 2017 and August 2018
Unfortunately I did not. Previously I have only been in the UK in 2013 for a short trip.
Overall it looks like my due to my misunderstanding on how the absences are calculated I will not qualify for settled status even with two excuses for those dates as I am currently not in the UK due to medical and personal reasons and it would be my third such absence. If the residence requirements were as explained in the video I still would have qualified as I have been in the UK long enough last year (august 2021 - august 2022). :/