The problem is that its stored in IndexedDB in the browser, which has a 2 GB limit. also FFmpeg (WASM), which renders the files, cannot process files larger than 2–4 GB. So the tool needs to be running either on the cloud or locally outside the browser like Adobe Premiere.
Thanks! How exactly do you have to wait? I tested it by adding around 200 MB, and it was added immediately since nothing gets uploaded it's just stored in the browser. Exporting and importing the project in a specific format is a really great feature to have. Thanks for suggesting it! I will add it to my to-dos.