That is because it is a swap partition and not an esxt4 partition.
Generally speaking, enabling the fstrim timer is all you need to do to get trimming running on all your partitions which support trim. systemctl enable --now fstrim.timer
You shouldn’t need to set discard flags.
Also, I will reiterate what someone else said in another topic that you are much more likely to get proper attention and better help if you use descriptive titles.