The best way to have consistent results is to add a record for USB sticks to
(Note: The example I'm about to post here-below applies only for plugging in one USB stick at the time, so it won't work for plugging in multiple USB sticks in different USB ports.)
The record could look something like...
/dev/sdb1 /run/media auto noauto,nofail,defaults,uid=1000,gid=1000,sync 0 0
/dev/sdb1 to the correct device special file for the USB stick ─ see the command below this paragraph ─ and
/run/media for whatever other mountpoint you desire.
The command that will tell you the correct block device for the USB stick is this here, to be entered in a terminal window after inserting the USB stick...:
Important however is the
sync mount option. The default is always
async, which means that data written to the device will be buffered and kept in memory until the system is under the least load, and then it will be synchronized with the physical storage medium.
sync tells it to synchronize with the storage medium immediately.
However ─ and this is important too ─ there are several things which determine the transfer speed and how quickly a write operation to the USB stick can terminate. The first of them is the USB transfer speed of the stick. There are significant differences in speed between the different USB standards ─ USB 1, USB 2 or USB 3. So it all depends on the speed of the USB port and the speed of the USB stick itself.
The second important factor is that USB sticks use flash memory, but do not support the TRIM command, nor do they have any wear-leveling logic built-in. This means that over time, they tend to wear out as you write more data to the device, and perhaps overwrite existing data.
Flash memory cannot be overwritten, so it is actually an operation in which the new data of the file that is to be overwritten gets written to a new location first, and then it must erase all cells that held the original data. And there's only a limited number of times you can do this.
A USB stick that has already been used many times before for writing data, "overwriting" data ─ i.e. copying and erasing ─ and that also is more than half full will begin to show significant performance degradation. And there is nothing that the operating system on your computer can do about that. It's inherent to the design of USB sticks.
SSDs usually also employ flash memory, but they support the TRIM command, and they commonly also employ wear-leveling techniques, in addition to a significant overprovision of the available storage space ─ or otherwise put, SSDs commonly have a significantly higher amount of storage capacity than what they are sold as, exactly so that they would be able to level the wear caused by write-and-erase cycles and write amplification. But that is of course why SSDs cost a lot more than USB sticks.
You can extend the life of a used USB stick somewhat by reformatting it and starting anew. It levels the wear somewhat, as opposed to when you keep on "overwriting" files on it with newer versions of the data.
Hope this helps.