You could try Cyberpunk 2077, Dishonored 1&2, Prey before giving any money to Ubisoft. + Half-Life 2, BioShock trilogy, Fear if you want more action.
If you aren't against rpgs go play Dragon Age:Origins, Mass Effect trilogy or Baldur's Gate 3. Or Alpha Protocol ?
If oldies doesn't scare you : Vampire Bloodlines, Deus Ex, Half-Life, Baldur's Gate 1&2, Planescape Torment, Thief 1&2, and some point'n click games also...
You should be able to sync any type of var with multiplayer_sync node. I don't remember how it is done thought.
To organize you can really use whatever method you prefer. I prefer to store datas into jsons/dictionaries and use arrays only to use the data for a specific purpose...
Also be carefull because you can't send a node on the network to another peer.
Hum it isn't I'll check it out thx.
Edit : fixed, thank you didn't pay attention and tick the box by mistake.