Hey! So I made a post in the discord, posting a video that Xisuma made about player graves. I feel like this would increase the challenge without removing keep-inventory.
Here's a link to the video to check it out yourselves!
This allows your items to be saved from lava and any other kind of death, with a function making sure nobody can steal your loot. It can be disabled, but by default there is a message sent in chat to tell you where you died in case you were lost somewhere deep in a cave.
I feel like this would add a lot more challenge to SMP without making it 'difficult' or rage inducing.
Thanks for reading, I hope it is added!