Thanks, everybody, for the suggestions.

I tried something like that.  I made sure that my phonebook was saved to
memory in Phone-1.  Then, I put the new SIM (SIM-2) into the old phone
(Phone-1) and copied ALL to SIM (without deleting anything).

I put the new SIM (SIM-2) with the copied info into the new phone (Phone-2).
I see a lot of duplicate entries that I think I can fix by finding the
right combination of "use SIM", "use Phone" or "use Both" for viewing
the Phonebook.

However, the unfixable thing is that everything was truncated in the
copying phase.  NO e-mail addresses or other info was copied from
Phone-1 memory to SIM-2.  Names longer than a certain number of
character were truncated, e.g., "LongFirstName LongLastName" got
copied as "LongFirstName Lon" or whatever the character limit is.

Every Name that had more than one phone number seems to have a
separate duplicate entry in Phone memory.  I.e.,

Name #1, #2, #3, e-mail (one phonebook entry on old phone)
becomes three separate entries in the new phone:
Name-1 #1
Name-2 #2
Name-3 #3

I now have to scroll through many more entries to get what I want.
(I used to do, maybe, a single letter "X" to get to the first X entry
and then "down" a couple of times to get what I wanted.  Now, it's
a lot more "down arrow" clicks for many names.

Maybe I was supposed to do it the opposite way: put the OLD SIM (SIM-1)
into the new phone (Phone-2) and copy from the SIM to the Phone.  But
it seems that the Phone would still have truncated info and split
entries as well.

That's why I think I want SIM-to-SIM copying of the phonebook.

That's something I didn't know.  Phonebooks are "csv" and readable in
Excel.  So maybe drag-drop-edit will work?

I didn't necessarily mean auto-Synch as you describe, but just an
easier way to update one phone from the other.  Just plain old copying
the most up-to-date phonebook to the less up to date phone would
be fine by me.

THANK YOU.