Hey there Gauthier! There is some fantastic progress happening.
The flexibility, PASSIVE REDUCTION, and approach to the Singing C are all developing well. Just be sure to get the magnifying glass out to be sure you are remaining PASSIVE when necessary.
I have a small concern about the mouthpiece buzz, it is, in your case creating a bit of lip interference which is affecting the sound.
I would recommend you keep working on getting the “Chin Down Corners In” aim for no buzz on the low C, and discover your sympathetic oscillation, it’s not quite there yet so I am losing a degree of the Body’s Concert Hall resonance.
Thank you for taking the time to record and share, it’s a fantastic effort.
Please book a 10-minute chat so we can have a look at what you are doing.