I've been getting a lot of bugs reported for this release, though it is performing fine on my test devices (which is annoying as it make the issue tricky to find let alone fix) and browser.
With the web version, is the issue with starting a new game from the main menu, or does the game simply not load at all (and if so, does it show the black screen with grey loading bar)?
For the desktop version, I've tested it on Windows 10 and 11 without the mentioned issues, but it is still possible there's a compatibility issue.
I've uploaded a debug version of the game that should output some log files to the save directory (normally found at C:/Users/<USER>AppData/Roaming/Dapplecap).
If possible, please could you replicate the error in the debug version and post the contents of this directory (as a .zip) or the text from the logs/godot.log file under the save directory?