Run out of RAM when backup to WebDAV drive

[MacKarp]

Hello, when you try to make backup to NextCloud (WebDAV) it will eat all your RAM/SWAP and there it would unmount NextCloud drive and throw error:

[Errno 5] Błąd wejścia/wyjścia

which translates to:

[Errno 5] Input/Output Error

Local backup file size: 22GB
RAM/SWAP: 16GB/2GB
Steps to reproduce:

1. Go to setting -> Online account and add NextCloud account
2. Mount NextCloud drive in Nemo
3. Choose NextCloud as backup destination
4. Wait until you run out of RAM
5. Few second freeze
6. Unmounted drive and [Errno 5]

This should fix problem:
check if network drive -> create temp file -> send to network drive -> delete temp file

Don't know what is first: Error or drive unmounted because it freeze my system for few second

Fully updated system:

Distro: Linux Mint 20.3 Una
Desktop: Cinnamon 5.2.7
Kernel: 5.15.0-33-generic x86_64
16GB RAM
2GB Swap