Wifi transfer reliability issues . . . (?)

[Som30ne]

A few days ago I transferred a large number of files and folders from one phone to another, using the Wifi transfer.

Steps performed:
On the source phone :
selected the desired directories
selected Copy Via . . . -> Wifi
And got the wifi transfer screen with the QR code

On Target Phone :
Started TC
Selected Wifi Transfer from the 'home' screen
Got the screen with the camera area to scan the QR
Scanned the QR
selected all the directories
Selected copy to clipboard
Opened the destination directory on the target phone
selected 'paste here'

In the first try - several times, I got a message that there was a disconnect,
and the screen with the camera area to scan the QR code appeared
When I scanned the QR again, it seemed to continue.

Since it happened several times,
I was unsure of the results.
At some point when it happened again, I selected 'cancel' and aborted the transfer.

I deleted all the content from the destination phone,
and started again (all steps of 'target phone' from above).
This time it seemed to work without any disconnections.

At the end of the operation -
I selected all the directories on both phones,
and selected 'properties' for the selected directories.

The results showed that 4 files were missing on the target phone.
I searched from the files and copied them.
I selected properties again on both phones, and saw that 40KB were missing
(file count was the same).

I searched again and saw that one file on the target phone was 20KB,
while on the source phone it was 60KB

* on both phones the files were copied from/to a directory that is not being used
by any other app that might or might not be running in the background.

There was no report of any error during the copy operation.

This made me wonder about the reliability of wifi copy functionality . . .

I would be glad to get any ideas or thoughts
if there is any way to make sure that in the future copying files this way would be accurate and reliable.