Big Sur - Time Machine structure
All three are normal for TM volumes created in Big Sur.
Explanations for 2 &amp; 3: you won't see the system volume in the Finder, but it will be available if you need to boot from the TM volume. The only reason for doing that would be to repair or restore the source.
Local Snapshots are stored on the source and are not designed to be accessed from within the TM interface.