That kind of thing just doesn’t work when you try to do things in a browser without making you constantly think that things are broken.

There’s some things you can’t really avoid dealing with that stuff for, but if it doesn’t really need to be a dynamic interaction with the service, you may be able to just write a script that runs on your server (either once or periodically) to download what you need as a batch, and then serve static results based on that to your users. It’s not only easier to implement when you can use that technique, but the UX is often better that way too…

the async nature of web stuff is really breaking my brain

I am being forced to learn async stuff and I kind of hate it…

I remember beating my head against the wall working through the details of Promises in JS a couple years ago when I needed to figure out how to trigger certain pieces of logic only after all of a large batch of slow, dynamic results were fetched – which the user would often want to interrupt and adjust as partial results came in… so, I know what you mean.