In the greater Northern Midwest were these temps can be the norm, many people have corn or wood pellet heaters. My sister entire house can be heated by theirs even if they lose power. They are not that expensive compared to a central heating system. It may be a waste of money in Texas, this is not a normal storm. However, my brother-in-law said it cut his winter heating bill nearly in half. I am having one installed in my unused fire place.
Pellet stoves that require AC are a fail.
“corn or wood pellet heaters.”
Just keep in mind those types of heaters require electricity to operate. You would be better off with a traditional wood or coal stove for emergency heat.
I have a gas stove, a wood fireplace, and an indoor-safe propane heater
Always have multiple backups.