Describe the solution you'd like
Some of the configuration options should be determined by the client whilst on servers:

• Enable Forgotten Graves
• Send Grave Coordinates
• Grave Drop Type

The rest of the options should be determined by the server at all times:

• Enable Grave Robbing
• Minimum OP Level Override
• Grave Retrieval Type
• XP Storage Type
• Max Custom XP Level

I'll need to look into this more.

Update:
I've been working on this feature this week. I didn't like how opinionated the original idea was so I added a new server-side setting called Client Side Options which accepts a list of settings that the client can control (comma separated). This means that each server can allow different settings to be controlled by the client.

I plan on writing some documentation for the mod, and testing this feature more/adding some polish, but once I'm done with that this will be released with the next update.

Release mc1.18.1-v2.4.1 adds this functionality. You can read about it a bit more here. Closing.