Texas and California seceding together is not plausible. They're deeply at odds. Nor is it likely that violence would erupt along state lines. The American two-party system isn't particularly divided in terms of states. All of it would occur in patches, in the streets, almost house-to-house, community-to-community, like Star Trek's 'Red Hour.' Most of the vulnerable - children, the poor, the elderly, the disabled, and unfortunately, the simply unprepared, would become casualties almost immediately.
There's two plausible scenarios under which this kind of violence would break out.
𝐎𝐧𝐞: Democrats win in 2024, and MAGAts all over the country start staging terrorist attacks on government offices, taking perceived liberals (members of the media, politicians, state officials) hostage, and/or killing them. It would not be quickly put down, but would continue to rage in random spurts for years.
𝐓𝐰𝐨: Trump gets into office in 2024, and immediately declares martial law, and begins using the cooperating members of forces of the federal government to hunt down and arrest his 'enemies' - members of the media, politicians, state officials, and anyone who resists following his orders. A lot of Democrats would disappear. It's probable that Trump would invite a military presence from Russia - whatever they have left that they can spare - to enter the US in order to assist in 'pacifying' the civilian populace, and in putting down whatever civilian police or military members who would not cooperate with his complete takeover into dictatorship. The Constitution would be abolished, and Trump would impose oaths of loyalty upon American citizens. Worldwide, Trump would begin issuing ultimatums and dropping nukes on cities and countries who do not accept his terms.
Either one of these scenarios would be a complete shitstorm from which the US would never recover.
I don't think this film will be helpful, because it will help encourage in the public mind the inevitability of this kind of conflict, and will offer distorted ideas about what such a conflict would entail, and what the issues really are - especially the notion that the conflict is necessary, and winnable. It's not.