Trying to understand why my FX30 to M1 speeds are so slow.

When I try to move my video files from FX30 to my M1 Macbook, with a USB-C to USB-C connection, my transfer speeds are very low. macOS doesn't give information about transfer speed but when I move let's say 70 GB of data, it takes about 35-40 minutes from camera to the external drive connected through USB-C. I know the external drive is not the culprit because I have another one connected through the USB-C port (and they're both connected to the same port) and when I try to move the same folder I just got from the camera in 40 minutes, it maybe takes 10 minutes to copy from one external drive to the other, which are both HDD spinning disk and again, they're both connected to the same port, which I try to avoid with the FX30 so both the FX30 and external drive can use full port speed if they need to. The only difference is external drives are APFS or MacOS Journaled formatted and I think CFExpress card inside the FX30 is ExFAT, but this shouldn't make that much difference.

I'm looking to buy an CFExpress card reader, but I really want to understand why there is such a big transfer speed difference, even though everything is connected via USB-C.

I'd appreciate any suggestions and opinions, thanks in advance!