I don't know what its like in the US but here in Australia, as you would know, electronics blown out by surges is very common. I lost a $3K iMac to a surge. But it was covered by insurance so not all bad.
The more I learn about Switzerland the more it sounds like a great place.
Also, is it advisable to make a backup of the USB Drive? I have spare 32GB drives.
For sure. You’re problems have prompted me to re-do my backup and to make sure it’s ext4, and to double check the master is ext4.