You are not alone... I have the same issue on my Apple Watch 4 with cellular. Unable to install Spotify on my Apple Watch 4 using the latest released iOS, Watch OS and Spotify updates. I spent hours with Spotify support trying all kinds of things to resolve the issue, but that was vain. Then, as Spotify suggested me to contact Apple, my Apple watch was replaced and re-paired as new. But Spotify wouldn't install on the Apple Watch. Conclusion: it was not my Apple Watch having an issue. Then I re-installed iOS from new on my iPhone and I still have the same issue. I let Spotify support know that nothing has fixed this issue. Hopefully a fix will be released soon.
Appvalley Won't Download Spotify Music Converter
Nov 28, 2018 7:34 AM
Download Spotify For Mac
May 09, 2020 AppValley & Tweakbox Status has you covered! I will inform you if any 3rd party Tweaked Apps For iPhone & iPad store is signed, so that you can download your Tweaked Apps like Spotify.