I was just reading about this, along with Texas including a plank about a stolen election and Biden is only "acting" President.
The short answer is no, Texas can not secede per SCOTUS. Scalia put it to rest. Doesn't mean they won't keep trying though.
"If there was any constitutional issue resolved by the Civil War, it is that there is no right to secede," the late Justice Antonin Scalia once wrote.
It wouldn't just be Texas alone, it would be the entire Southern Border.
Because a large share of the Strategic Oil Reserve is housed in Texas, that would be used as a talking point to declare war on the breakoff states. Except it won't happen. American servicemen will not start killing each other on US soil. It just won't happen.
California won't go Blue, it would split in half. Tons of Republicans in CA.
Before the pandemic, I would split time in California, Texas and New York. I can say the complexities of running businesses in CA is exponentially more difficult. I would compare it to being subjected to primitive dentistry. Gavin Newsom aka Dollar Store Obama is a complete and total idiot. London Breed is an imbecile. I've never seen widespread public policy that worked like some kind of medieval torture chamber before.
Texans believe they live in the greatest state in the entire union. When I'm there, it's true. When I'm not there, it's conflicting.
Do you think Texas is going to worry about what SCOTUS says? Separation will be about survival, not formal policy and law. I feel badly for honest hard working good decent every day working class people stuck in Big Blue Cities and majorly Blue strongholds. But Texans will hold fast to the belief that other states made their own messes, they can soak in their own filth, and the Lone Star State comes first.
So the first thing that would happen is people like myself who own property in multiple states, including Texas, the ham fisted overlords that control Biden and the rest will try to seize my non Texas property. If you want to be part of the "New Texas and Southern Border", then we are going to take the rest of your s--t from you. That's exactly what would happen.
If you can't enforce it with a bunch of guns, then you can't enforce it. SCOTUS can say whatever it wants, Americans in the military and law enforcement are not going to go to war with against Texans and the Southern Border states. This is not the Handmaid's Tale. You can't compel humans to shoot at their neighbors. There is no law, no mandate, no speech you could give, no policy, no SCOTUS ruling, that is going to change the current human condition in America today.