Dolphin is crashing when taking a backup.

Hello. I am planning to move my machine from AlmaLinux 9.5 KDE to Debian 12.8 KDE. And a friend lead me a 2TB external hard drive to take a backup of 1.3TB (That's openZFS 2X4TB RAID 1). Fortunately. Dolphin had crashed 2 times now when reaching around 1TB.

I know a lot of factors could effect this, the RAM or external hard drive, but I cant say that RAID 1 could be related. Any way I can check or test to find the issue? I know about memtestx86 for RAM but I don't know what to do about the external hard drive.

If you have any idea that can help please advise me.

Thank you.