Am I still avoiding my todo list? Shamelessly so!
Not sure if you're on iOS or macOS. If you're on iOS, I just cobbled together a quick shortcut to have a go at this.
It's a little messy, and querying Reminders still takes longer than I'd like, but this might just serve while you're waiting for an update. Looks like Shortcuts can't access a reminder's alert, so we can't set an alert automatically.
Once installed, this should appear in your share sheet. Tap the "..." icon in the top right hand corner of a GoodTask reminder's card, then share, and select this shortcut from there.
If you're on macOS, there's probably a way to do something like this via AppleScript? Of course, this may be rendered redundant by something that's already being worked on in the app...