(i am on windows)
We discussed this issue on Discord. After sharing the full output of the debugging section, it was determined that there were too many sound clips. There is currently a limit of 64 sound clips in Pencil2D when exporting. This will be increased at some point, there are some technical challenges which make it unlikely to be done soon however.
We always recommend breaking up larger projects into multiple smaller projects, and combining them afterwards with a video editor. This practice, in addition to reducing the risk of loosing work, should help avoid scenarios like this.