In https://github.com/elastic/elasticsearch/pull/88639 we introduced a new setting that allows configuring a maximum headroom in disk watermarks that helps reducing the waste of disk space in large disks. The disk health indicator should take that new setting into account to avoid reporting issues when there's still room for new data in the cluster. 

https://github.com/elastic/elasticsearch/blob/6ec31ed1533e6aaf8fc6dabda5e419f5dce984fa/server/src/main/java/org/elasticsearch/health/metadata/HealthMetadata.java#L193-L199

Those calls should take into account the available max headroom.
server/src/main/java/org/elasticsearch/health/metadata/HealthMetadata.java
}
        @Override
        public int hashCode() {
            return Objects.hash(
                describeHighWatermark(),
                highMaxHeadroom,
                describeFloodStageWatermark(),
                floodStageMaxHeadroom,
                describeFrozenFloodStageWatermark(),
                frozenFloodStageMaxHeadroom
            );
        }
        public static Builder newBuilder() {
            return new Builder();
        }
        public static Builder newBuilder(Disk disk) {
            return new Builder(disk);
        }
        public static class Builder {
            private RelativeByteSizeValue highWatermark;
            private ByteSizeValue highMaxHeadroom;
            private RelativeByteSizeValue floodStageWatermark;
            private ByteSizeValue floodStageMaxHeadroom;
            private RelativeByteSizeValue frozenFloodStageWatermark;
            private ByteSizeValue frozenFloodStageMaxHeadroom;
            private Builder(Disk disk) {
                this.highWatermark = disk.highWatermark;
                this.highMaxHeadroom = disk.highMaxHeadroom;
                this.floodStageWatermark = disk.floodStageWatermark;
                this.floodStageMaxHeadroom = disk.floodStageMaxHeadroom;