About read and write speed

[yyy33]

When I mounted WebDAV, the download speed was only around 6MB. But with other file manager mount can be 11M. How should I do

Below is my configuration file

#default binds remote to /sdcard/Cloud/*
BINDSD=1
#relative to /storage/emulated/0
SDBINDPOINT=.rclone/dav
#relative to /storage/emulated/0
SDSYNCDIRS=
#root directory of share
SUBPATH=

PROFILE=0

ADD_PARAMS=--attr-timeout 1s --vfs-read-chunk-size 9M --vfs-read-chunk-size-limit off --cache-chunk-size 3M --cache-chunk-total-size 1G --cache-workers 6 --cache-info-age 6h0m0s --dir-cache-time 5m0s --poll-interval 1m0s --vfs-cache-mode writes --buffer-size 128M --vfs-read-ahead 256M --transfers 4 --vfs-cache-max-age 1h0m0s --vfs-cache-max-size off --vfs-cache-poll-interval 1m0s --vfs-write-back 5s --write-back-cache --max-read-ahead 3M --uid 0 --gid 1015 --dir-perms 0775 --file-perms 0644 --umask 002 --log-file /sdcard/.rclone/rclone.log --log-level NOTICE
REPLACE_PARAMS=0