I am a retired college teacher and have taught many classes of American and Texas state history. It is a shame that the money, acting talent and film expertise could not have been put to better use in telling a more accurate (and compelling) story of the birth of the Texas Republic. Read Lone Star: A History Of Texas And The Texans (T.R. Fehrenbach) for a pretty good understanding of the period and its players.
I personally prefer “Lone Star Nation” by H.W. Brands. He is a professor at Texas A&M yet they didn’t back the book very strongly. He documents his research thoroughly (Almost 40 pages of notes and sources) - but he lets the facts play out as they are. Unfortunately it seems the current thinking is that ALL history books must somehow reflect current political correctness, even if it takes outright lying.