maybe i am reading my data wrong or we are looking at two different data sets. i am looking at nyt_ts csv. are you unrolling the date field into raw minutes starting from wednesday 00:00 by hand, or relying on and trusting your graphing tool to do it properly for you?
I was using a chart tool graphing some points in the raw data at where I saw big jumps for Biden. You have spent a lot more time on it and I defer to your judgement. I am not an excel expert by any stretch