While I had the LCD out I tried it on the board a little moved
it around. It has those rubber conductive connections. I did
get bright flashes on some parts of the display, the word
"AGE" lit up brightly, so the display works.

Let's apply Sherlock Holmes' rule about eliminating the obvious.

If the display flashes or briefly displays "something", the problem might be
the contacts.

Try carefully cleaning the contacts on the board. You might also try
cleaning the conductive-rubber contacts on the LCD, but this requires using
a lint-free swab, and "rolling" (rather than rubbing) the swab over the
contact surfaces. Be vewy, vewy kehful.