I did find an interview with the showrunner of season 4. He stated the ending was intended to be ambiguous. He also stated the portal was open for good linking the two earths permanently.
I won't link to the article as it gets political at the end. :rolleyes:
Finished the final season last night. Really enjoyed the show although it wasn't clear where those people in the final scene are coming from or why.
Plan to read the book in the near future. Free from Amazon.
The remote is a challenge. The Apple TV 4K does accept IR commands, the codes should be on the internet somewhere. I find the remote app in iOS to be somewhat better, especially when it comes to entering ID's and passwords in the apps.