Thanks for reply, AndyHull
The arm with the the hooked end, was broken - the part, that connects with the setting lever.
I could feel that prior to dismantling, when crown pulling in/out quite weak without tension.
Thanks for talking through this with me. It’s funny I search ETA 2447 all over but it wasn’t until I search “ETA 2447 diameter” that info about the stem appeared.
I’ve ordered a 2360 stem - hopefully problem solved.