The delay is to do with process and assembly of evidence. The police have said it is a very complex case, there is a mass of evidence and they need to assemble it into a coherent set of accusations and supporting information.
Mr Lynn was charged late on Thursday by police. It is a matter of law that he is then brought to a court, I think a magistrates court or in Victoria, a bail court, as soon as practicable, where police formally present the charge or charges to a magistrate. The issue of bail is then raised. In this case, no application was made and would have been refused. It is rare for bail to be granted in the case of murder and manslaughter. The magistrate then formally remands the accused in custody, sets other conditions such as welfare and health checks, and sets a date for the accused's next appearance. There are usually time limits on how far this can be pushed into the future, and judges do not like delaying any of these stages or ultimately the trial. However, timing is determined by the complexity of assembling a brief of evidence for the next court to consider, the availability of witnesses and also the court calendar. The reason for this apparent rigmarole is that at each stage a person (magistrate, judge) unconnected with the investigation has to be convinced that the person should be charged and that if they are to be detained, that such detention, is lawful, i.e. justified by law. It is to protect the accused but ultimately all the community from the exercise of arbitrary power.
Mr Lynn's trial may not begin until the second half of next year. Unless of course he pleads guilty... then its over in a ix weeks or so.
The process is detailed in this document: https://content.legislation.vic.gov.au/sites/default/files/2021-10/09-7aa084 authorised_1.pdf
