A support pet would basically be the healing twilight. However, that is not the morph for damage dealers.
As posted above, the healing twilight is good for healing Sorcs, but ofc the twilight can die so it is not 100% reliable. For DPS many top sorcs run pets though there is some trial content that pets are not recommended due to mechanics in the fight were a pet will increase the damage for the group.
Here is a healing build for you to get some ideas. https://alcasthq.com/eso-magicka-sorcerer-healer-build-pve/
and a DPS build https://alcasthq.com/eso-magicka-sorcerer-pet-build-pve/