I’ve been reading that a bubble website or app has problems handling a lot of users, so could I just use bubble to make a program that people can download and then run offline? If not, what services let me create this without coding?
Try Wappler. Bubble isn’t suitable for your use case.
You can wrap your web application inside a desktop app and use offline notifier to inform your users about their internet connection.
Store the offline data inside the browser cookies and have it pushed whenever the connection re-establishes. It’s a complex build though.