He [Trump] may want the appearance that he welcomes “sunlight,” but it’s doubtful he wants the actual sun shining on this courtroom for all to see. Trump and his lawyers know better than anyone that a televised trial would likely backfire on Trump in the 2024 presidential election by reminding voters that he’s a lying, whining monster who tried to end our democracy as his last act in office.
The people who would see him in trial and decide that he’s unfit already think he’s unfit - there’s nothing to be gained. This would convince no one as his supporters would still vote for him if he was a vegetable at this point.