Synology time machine
“How_to_back_up_files_from_Mac_to_Synology_NAS_with_Time_Machine.
This will let you p[lug in a usb drive to a synolgoy nas and then from there configure an AFP share that mac’s time machine software will find and then allow network backups. It is still on site so it isn’t totally secure and reliable. But it is a pretty good use of a 2tb drive and a NAS. The initial backup is kind of brutal but then anything after that should be a bit better and faster. YEY for convenience