I'll use it to update the OS, then start restoring it to its original condition. I figured Etcher's going to be cool to warn that the drive was overwritten. That's my post 's intent.
I plan a small partition next to the Home partition. I'll backup my new Home folder and transfer Timeshift data there. I 'm currently using LLOS 18.04 and have made some customizations and hope to get as many of them back as possible by replacing the new files with the old ones. Hopefully 4 GB would suffice for the backup field.
For this, I'll possibly look at Ventoy.