Given the details you have provided for your case, sounds like there could be a lot of reasons that IRCC requested an interview. I saw you said that you ordered your GCMS notes, so wait for those to arrive. Once they do, you will have to really read through it ,and you should be able to find a comment from one of the officers on the case stating exactly why they have decided to request an interview for your case. Take careful note of it and gather as much evidence as possible to address their comments.
Unfortunately no matter how much details you tell us about your case, there is still no one in the entire world who can predict the delays due to the nature of the pandemic. They have put thousands of couples into a similar situation to what you are going through - all stuck in a limbo without the faintest idea of a timeline for when the process will be completed. It is terrible that this is happening and I am sorry that you guys have to go through this, but unfortunately no one has any idea of the future at this point.
Thank you so much for your help, really appreciate.