I play on All The Mods, and found myself losing all my Cyberware on death, without it even dropping to the ground. Just poof, gone.
Neither of the 2 Cyberware's gamerules nor the keepInventory rule affect that in any observeable way.
There's, however, a mod called Tomb Many Graves in the pack which saves your items on death in a tombstone. I think it's what causes the issue, but still would like some advice.

Update: uninstalled Tomb Many Graves, nothing changed. There must be smth else that I missed.

I'm dumb, it's cyberware_keepCyberware