They fare poorly.
An attorney is considered an officer of the court. Their word is considered ethical gold in court. A non-lawyer has ZERO gravitas before the court, and so everything he/she says is assumed "suspect" before the court.
I was involved (respondent) in a case where the factual documentary evidence was incontrovertible, public record, and it completely supported my case. It seemed such an obvious slam dunk that I didn't hire counsel. The other side's attorney argued on a pro-forma basis to dismiss my motion to dismiss, and the case continued. I am certain that if I had hired counsel and my counsel had said the exact same things I said, the case would have been dismissed.
The courts really dislike talking directly to petitioners and respondents.