FullCalander, Angular 17 type errors

Question

I'm a bit stuck. I'm attempting to use FullCalander 6.1.11 with Angular 17. I'm using node 18.18.2.

I'm receiving several type errors on ng serve compiles. The imports in bold are not found. If I add '/' to /core/, this quiets this compile error. Why would this happen?

import { DatePointApi, ViewApi, EventApi, EventChangeArg, Duration, EventDropArg, PluginDef } from '@fullcalendar/core';