Hello @JacobRiski-8238 ,
I have created a short video to show all the process involved in adding external contacts to Teams and invite them for the meeting. I have included the video in my blog as below. Hope, it helps you !
Direct YouTube Link: https://youtu.be/J1-K7ZEOF4U
Please mark as "Accept the answer" if the above steps helps you. Others with similar issues can also follow the solution as per your suggestion