That may be a limitation with libinput scrolling methods perhaps. This
page describes those methods (valid for both Wayland and Xorg environments).
I don't have direct experience with Deepin, but if 'libinput-tools' is installed then you can query the current input device configuration with
Code:
sudo libinput list-devices
There will be a section pertaining to the touchpad device and you can share that output here for others to advise further.