(as initially stated: this thread is explicitly not about 3rd party software like VLC that bring their own software decoders, it is about the Fairphone3 and the software/hardware decoders in system Android, that the apps like Eleven and the documentsui should pick up on, as they do not have any decoding ability)
FP3 on Android R /e/ 1.0 picks up the codec and plays .ogg, with either Vorbis or Opus, in the Music app (eleven) and via Files (documentsui). So this seems resolved to me @madhatter as soon as you can update
05-29 05:35:40.437 1023 7148 I CCodec : Created component [c2.android.vorbis.decoder]
05-29 05:35:40.495 769 6495 I msm8974_platform: platform_check_codec_backend_cfg:becf: afe: Codec selected backend: 0 updated bit width: 16 and sample rate: 48000