I am able to link my Xbox Game Pass for PC with EA Play. They linked up perfectly. However I faced an issue of unable to download the game I want, specifically, NFS Heat. It stuck at the stage of "preparing" and "calculating time".
After some trying, I found a workaround. If anybody is having same issue, hope this could walk you through. You may try it out to check if it works for you too.
Basically, I started a download for a random game and it went to queue list due to the active download should be NFS Heat. NFS Heat stayed at "preparing" stage with no download at all. I can't even cancel the download or pause it. As well, I was unable to send my queue for that random game to download first. So, I forced exit EA Desktop app and reopened it, ended up the download was broken for NFS Heat. I was able to send queue list game to download first now and it worked out. Download started for that random game and NFS Heat was automatically sent to queue. I cancelled the NFS Heat from download queue list and waited the random game to complete the download. After that, I initiated the download of NFS Heat again. Voila, NFS Heat started to download at last.
I guess they are some bugs lie in either the EA Desktop app or during the process of linking with Xbox Game Pass. Hope this helps.