Thanks for your help! Sorry it took a while to reply, been a hectic week.
I ended up doing something similar on my own with a system that figures out delta changes to an acceleration map I use for the inventory and then sends the updates to all clients that have asked to receive them rather than everyone. In the end I figured this would be a better option than having everything synced all the time. Clients can subscribe to getting updates for an inventory until they request to unsubscribe. This lets you keep your own inventory synced all the time, for example, while chests and stuff only sync while you’re looking in them.