Solution of Strict limit of write cache / 0s sync time policy for usb devices by default - #12 by megavolt was merged to AUR (en) - udev-usb-sync. So there it is solved, and I am (and a lot of others are) pleased with no waiting time for usb devices.
But it is still not the default on Manjaro.
My account is still deactivated. So, I cannot do anything there. Well and rationally I don’t care, because I cannot do anything there, even if I would have an account there. 
Copy that. Closing.
The package has been added to the repo as of 2025-03-27T23:00:00Z
It can be synced using
sudo pacman -Syu udev-usb-sync
To avoid confusion with our repo - the package on AUR has been renamed to arch-udev-usb-sync - so anyone having the old AUR build should be automagically synced to the repo version.
//EDIT
2025-04-02T05:45:00Z:
On March 30. 2025 the package was added to the Packages-Root and thus Manjaro 25 release review after that date will default to use the helper.