DownYouGo Add-on 1.21+/1.20+

Imagine losing 75% of your health in real life. It's unlikely that such injuries or illnesses would allow you to even walk afterward. Therefore, to enhance realism, the mod DownYouGo introduces a new feature in Minecraft. Now, at low health, the player will fall as if they had suffered a serious injury and will no longer be able to move.

Only other players can save the character, coming to their aid and providing healing. To do this, you need to approach the injured player and crouch. Quite an interesting feature for multiplayer.