The Austin Chronicle is a free weekly print alternative newspaper in Austin, Texas. It has a law question-and-answer column written by Luke Ellis. In this issue, a reader asks how an independent candidate gets on the ballot in Texas, and the author is detailed and accurate, and shows how bad the law is. See the column here.
As the columnn says, any 2022 independent candidate must file paperwork before the end of 2021. However, if the Texas 2022 primary is postponed due to any court changing the redistricting, there would be some relief from such an early deadline. The column did not mention there there is also a ballot access lawsuit pending in U.S. District Court that, if it wins, would change the procedure.