When booting into recovery from an external drive such as the one created using the DosDude1 installer, why does the Time Machine 'Select a Restore Source' menu show both my internal HFS+ TM drive as well as my APFS SSD boot drive?
Further complicating matters is that if the TM drive is selected and you go into the 'Select Backup' menu screen, the 'Restore From' drop down is grayed out and defaults to the SSD boot drive. This makes a full TM restoration from the TM drive to the boot drive impossible.
I haven't tested this but I'm assuming the only way to perform a full TM restoration from a TM drive to a boot drive would be to format the boot device first so there's nothing on it. Is my assumption correct?
In the meantime, I'm going to look at some other backup and recovery utilities, but would like to get a definitive answer on the above. The behavior of TM in Catalina is far different than that of High Sierra or any Mac OS preceding it.