Thanks for your reply 
That's the question. I am not sure.
But I don't know where I could tune these server-side move settings within nextcloud.
You mean copy/move tools? Well, mainly the built-in copy/move function within Windows Explorer and - as mentioned above - exiftool via CLI.
I mean it didn't improved the move speed at all as I added --disable move to my rclone mount command.
I just removed all unneccessary flags.
Here my rclone config:
[nextcloud]
type = webdav
pass = XXX
url = https://nextcloud.DOMAIN.TLD/remote.php/dav/files/USER%20NAME
user = XXX
vendor = nextcloud
### Double check the config for sensitive info before posting publicly
and here my rclone mount bat file:
@set RCLONE_CONFIG=rclone.conf
@set rclone=C:\rclone\rclone.exe
@set logfile=C:\rclone\log.txt
@set log=--log-level=DEBUG --log-file=%logfile%
@del %logfile%
start %rclone% selfupdate %log%
start %rclone% mount nextcloud:\ N: --volname Nextcloud --vfs-cache-mode full %log%
And as proposed, I used rclone move command to test the performance:
C:\rclone>rclone move "N:\Pictures\2009\testfolder" "N:\Pictures\2009\testfolder-2" --include "*.JPG" -vv
2023/10/10 19:45:40 DEBUG : rclone: Version "v1.64.0" starting with parameters ["rclone" "move" "N:\\Pictures\\2009\\testfolder" "N:\\Pictures\\2009\\testfolder-2" "--include" "*.JPG" "-vv"]
2023/10/10 19:45:40 DEBUG : Creating backend with remote "N:\\Pictures\\2009\\testfolder"
2023/10/10 19:45:40 DEBUG : Using config file from "C:\\rclone\\rclone.conf"
2023/10/10 19:45:41 DEBUG : fs cache: renaming cache item "N:\\Pictures\\2009\\testfolder" to be canonical "//?/N:/Pictures/2009/testfolder"
2023/10/10 19:45:41 DEBUG : Creating backend with remote "N:\\Pictures\\2009\\testfolder-2"
2023/10/10 19:45:41 DEBUG : fs cache: renaming cache item "N:\\Pictures\\2009\\testfolder-2" to be canonical "//?/N:/Pictures/2009/testfolder-2"
2023/10/10 19:45:41 DEBUG : IMGP1540 - Copy.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1540.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1541 - Copy.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1541.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1542 - Copy.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1542.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1543 - Copy.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1543.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1544 - Copy.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1544.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1545 - Copy.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1545.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1546 - Copy.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : IMGP1546.JPG: Need to transfer - File not found at Destination
2023/10/10 19:45:41 DEBUG : Local file system at //?/N:/Pictures/2009/testfolder-2: Waiting for checks to finish
2023/10/10 19:45:41 DEBUG : Local file system at //?/N:/Pictures/2009/testfolder-2: Waiting for transfers to finish
2023/10/10 19:45:44 INFO : IMGP1541 - Copy.JPG: Moved (server-side)
2023/10/10 19:45:45 INFO : IMGP1540.JPG: Moved (server-side)
2023/10/10 19:45:46 INFO : IMGP1540 - Copy.JPG: Moved (server-side)
2023/10/10 19:45:46 INFO : IMGP1541.JPG: Moved (server-side)
2023/10/10 19:45:47 INFO : IMGP1542 - Copy.JPG: Moved (server-side)
2023/10/10 19:45:49 INFO : IMGP1542.JPG: Moved (server-side)
2023/10/10 19:45:50 INFO : IMGP1543.JPG: Moved (server-side)
2023/10/10 19:45:50 INFO : IMGP1543 - Copy.JPG: Moved (server-side)
2023/10/10 19:45:52 INFO : IMGP1544.JPG: Moved (server-side)
2023/10/10 19:45:53 INFO : IMGP1544 - Copy.JPG: Moved (server-side)
2023/10/10 19:45:54 INFO : IMGP1545.JPG: Moved (server-side)
2023/10/10 19:45:54 INFO : IMGP1545 - Copy.JPG: Moved (server-side)
2023/10/10 19:45:57 INFO : IMGP1546 - Copy.JPG: Moved (server-side)
2023/10/10 19:45:57 INFO : IMGP1546.JPG: Moved (server-side)
2023/10/10 19:45:57 INFO : There was nothing to transfer
2023/10/10 19:45:57 INFO :
Transferred: 0 B / 0 B, -, 0 B/s, ETA -
Checks: 14 / 14, 100%
Renamed: 14
Server Side Moves: 14 @ 28.846 MiB
Elapsed time: 16.5s
2023/10/10 19:45:57 DEBUG : 2 go routines active
So the performance seems the same whether I use the rclone mount command or Windows Explorer/exiftool...
Here the rclone debug logfile: