I was taught to place a comma before the “and” preceding the last item of a series. My adult daughter and son told me several years ago that English teachers were moving away from that.
I probably use it about 50% of the time so over time I’m half right. 😁
Lot's of
stuff crap that is acceptable in common speech has also become acceptable in "writing and journalism".
"Since" and "because" are becoming synonymous. One is an expression relating to time passed and the other is an expression of "the result of". But, it's OK (okay?) to use them interchangeably now it seems.