Can you please confirm which version of the SDK you are using? Also, the iOS SDK currently does not have support for using filters with a custom meeting UI. They are only available through the default meeting UI. You should be able to select the blur background programmatically though, depending on the version you are using.
Thanks for confirming the version you’re using. That SDK version does not have support for the blur background. The Meeting SDK usually has the same features as the client for a given version, so it’s always a good idea to check out the client release notes. In the case of blur, this was added to the client in v5.6.6, meaning that any version of the SDK from 5.7.1 onward will have support for this.