I use the 'Containerise' plugin along with the following configuration (which I am constantly tweaking) to keep the big tech companies isolated from each other and the rest of the web. https://addons.mozilla.org/en-US/firefox/addon/containerise/ I'm also increasingly using it to keep their various properties isolated from each other (eg. keeping Bing separate from the rest of Microsoft) to reduce tracking even furthe…
This add-on has the same problem as Temporary containers. If you want to isolate Facebook and click a link to Spotify it will open Spotify in the Facebook container :( So far only the Google/FB container add-ons do this right.
If you are talking about the Temporary containers extension, that's not the case. The extension is not the most easy to use, but it certainly supports opening Spotify in a different container when clicking a link in FB. You either don't have the Navigation→Target Domain set to Different from Tab Domain & Subdomains or you have Exclusion Patterns set which exempt Spotify.