Is it permissible for a husband to reconcile with his wife whom he divorced via a text message, and for which a final, irrevocable divorce (baynunah kubra) decree was issued, knowing that this was the first divorce and was not preceded by any other divorce?

If the reality is that you divorced your wife with a single pronouncement, then this is a revocable divorce. You have the right to take her back without a new contract if she is still within her waiting period (iddah), and with a new contract if her waiting period has expired. Be careful not to hasten in uttering divorce and using it as a means to solve problems, and avoid irritability and anger.