Slow download speed

[robertoohoho 4]

Hello,

Since a few months I get very slow speed when downloading files from a browser (Waterfox) or with Bittorrent. Without VPN, the speed is: download 926.98 Mbps, upload 928.36 Mbps.

As a test, I downloaded a 6GB file with AirVPN: the speed starts around 5MB/s but quickly decline to 1MB/s (see video).
I tested the same download with ProtonVPN and I get a steady 18MB/s.

I also did some tests with Speedtest:
AirVPN, France -> Maasym, Alblasserdam, NL: Download speed 127.97 Mbps, Upload speed 128.50 Mbps (128/8 should give me around 16MB/s).
Proton, France -> France: Download speed 156.46 Mbps; Upload speed 452.43 Mbps.

I'm on Mac silicon under Tahoe with RAM and room.

Any idea what could cause this problem? 

Cheers.

[Edit] I added a log.

Eddie log.txt

Edited ... by robertoohoho
Added a log