Will contests are litigation cases. They are complicated because the Rules of Evidence and the Rules of Civil Procedure must be observed. A judge is under a legal obligation not to favor one party over the other so (s)he will not be able to tell you what to do or when to do it if you try to represent yourself. A person may have a good claim but can’t get the claim to the jury because they don’t know the rules. Unlike Hollywood movies, you can’t just talk to the jury and tell them your story. Obviously, contesting a will is a daunting task which requires the consideration of a multitude of factors. An attorney who handles litigation knows the rules and will be able to present the case to the jury for them to decide the case on the merits.
Can I contest a will without a lawyer? Legally you have a right to do that but practically you would be foolish to try.