onRespawn

@SubscribeEvent
    public void onRespawn(PlayerRespawnEvent event) {
        PlayerEntity player = event.getPlayer();

        player.getCapability(HealthCapability.HEALTH_CAPABILITY).ifPresent(health -> {
            if (player.getMaxHealth() >= 2.0F && player.getMaxHealth() <= 20.0F) {
                player.setHealth(health.getMaxHealth());
                player.getAttribute(Attributes.MAX_HEALTH).setBaseValue(health.getMaxHealth());

            } if (player.getMaxHealth() >= 22.0F) {
                player.setGameMode(GameType.SPECTATOR);
            }
        });
    }