I still have some crazy idea to franken up some old apple watch cases with mechanical movements.
There were some threads here a few years back where someone did do a custom rectangular mechanical movement with an offset winding stem.
The movement caliberof the OP watch is not noted. The dial is indicitive of a ladies style. The smaller 18mm movements even the 684 chronometer do not have much value.
The 56x automatic movements (and related.) are probably some of the best mass produced movements ever made (and probably will be since there is no longer a need for such things.) Cases though remain a bottleneck. Back in the day before quartz and timex, a lot of swiss movements were sold in the rough. These then cased locally. Sometimes under license.
Eventually there may return to where custom cases can be done. Through manufacturing like 3D printing. Modern ideas of IP and copyright have only been around for a couple generations, and even then only in some cultures. The arguments back in the 19th century was the man had to do the work to protect the women and children. Granted Dickens and Poe did not like that their work was being pirated. Ever wonder why the old west town had a newspaper. They were also outside the law printing things withour paying the likes of Dickens, Tennyson or Longfellow.
Edison changed this with his ego. Then the railroads declared they were immortal, and had the same rights as a person. Especially when it came to the ownership of ideas. Nothing new, the old guilds had the right to destroy inferior work, or prevent women from owning tools.
It remains in Omega's best interest to sell you a new watch from the latest catalog. There is no real value in the vintage stuff other than reputation and prestige.
So that leaves, what the rest of us do, which is to check online sites like eBay daily if not hourly for empty watch cases what are compatible with the movements.