[Android Software/Hacking General [Developers Only]] bmg1001:
Alrighty. Testing on an Essential PH-1 with Android 9.0 Pie. Using the Unrestricted libraries. I only tested on my SoundPEATS Q30 (CSR8645) and my Sony MDRXB950BT for now. Getting the bluetooth logs was a little troublesome as it sometimes wouldn't make a log. For the audio test, I streamed an MQA track from Tidal. As for making the connection, I had to unpair and pair each device every time as it would keep auto-connecting instantly. If there are any changes I should make to the way I tested this, please let me know!

I'm a little worried that maybe I didn't test things correctly because the MDRXB950BT is already on the list as supporting 512+ kbit/s SBC but from what I see in the log, that may not have been the case for me. (Also, fair note, the MDRXB950BT has three audio modes on it. Default is SBC only, Priority Mode supports AAC, SBC, and aptX, with bias towards the higher-quality sound, and Stable connection priority mode just chooses whatever makes the connection the most stable. My headset was on Priority Mode.)

Here are two logs for the SoundPEATS headset.

Connection:
10:cd:b6:00:d7:5b (Essential Phone) → c0:7a:a5:00:af:19 (Q30)

Supported codecs:
Audio non-A2DP (aptX - 16000 32000 44100 48000, Stereo)
Audio SBC (16000 32000 44100 48000 | Mono DualChannel Stereo JointStereo | block: 4 8 12 16 | subbands: 4 8 | allocation: SNR Loudness | bitpool: 2..53)
Audio SBC (44100 48000 | Mono DualChannel Stereo JointStereo | block: 4 8 12 16 | subbands: 4 8 | allocation: SNR Loudness | bitpool: 2..53)
Audio non-A2DP (aptX - 44100 48000, Stereo)
Audio MPEG-2,4 AAC

Used for audio:
Audio non-A2DP (aptX - 48000, Stereo)
Audio SBC (44100 | DualChannel | block: 16 | subbands: 8 | allocation: Loudness | bitpool: 2..53)

Latest SBC Bitpool value: 53

Connection:
10:cd:b6:00:d7:5b (Essential Phone) → c0:7a:a5:00:af:19 (Q30)

Supported codecs:
Audio non-A2DP (aptX - 16000 32000 44100 48000, Stereo)
Audio SBC (16000 32000 44100 48000 | Mono DualChannel Stereo JointStereo | block: 4 8 12 16 | subbands: 4 8 | allocation: SNR Loudness | bitpool: 2..53)

Used for audio:
Audio non-A2DP (aptX - 48000, Stereo)
Audio SBC (44100 | DualChannel | block: 16 | subbands: 8 | allocation: Loudness | bitpool: 2..53)

Latest SBC Bitpool value: 53

And here is the Sony MDRXB950BT

Connection:
10:cd:b6:00:d7:5b (Essential Phone) → 10:4f:a8:71:b2:51 (MDR-XB950BT)

Supported codecs:
Audio SBC (44100 48000 | Mono DualChannel Stereo JointStereo | block: 4 8 12 16 | subbands: 4 8 | allocation: SNR Loudness | bitpool: 2..53)
Audio non-A2DP (aptX - 44100 48000, Stereo)
Audio MPEG-2,4 AAC
Audio SBC (44100 48000 | Mono DualChannel Stereo JointStereo | block: 4 8 12 16 | subbands: 4 8 | allocation: SNR Loudness | bitpool: 2..53)
Audio non-A2DP (aptX - 44100 48000, Stereo)
Audio MPEG-2,4 AAC

Used for audio:
Audio non-A2DP (aptX - 48000, Stereo)
Audio SBC (44100 | DualChannel | block: 16 | subbands: 8 | allocation: Loudness | bitpool: 2..53)
Audio non-A2DP (aptX - 48000, Stereo)
Audio SBC (44100 | DualChannel | block: 16 | subbands: 8 | allocation: Loudness | bitpool: 2..53)

Latest SBC Bitpool value: 53

Again, if I messed anything up or if the logs don't match up for any reason, please let me know! I always use wireless audio so I'm always willing to help improve it.