Very easy to fix. But in case I ever encounter this again or you dear reader encounter this for the first time, here’s the fix:

1. Open Nuget from within VS2019
2. Beside sources, click settings
3. Now click Add
4. In the repository name, type Nuget. Type what ever you want really. It doesn’t matter
5. In the URL, type the following: https://api.nuget.org/v3/index.json