I used KDEConnect daily, but across several devices and networks I've noticed that find file transfers regularly get interrupted and "fail". As is par for the course for networking errors on Linux systems, it's completely unclear what fails. But in the end I've found KDEConnect is only suitable for sending small files.

If you send 100+ photos it won't work consistently. Or if you try to send one big file it'll typically interrupt somewhere in the middle. It doesn't seem to have any internal mechanism to recover and restart file transfer