I don’t know if you’re still working on this, but I just found it!
The motion you’ve created really sells a “calm and inviting” ambient effect. If that’s the direction you’re planning, here are my two cents:
Slowing down the trails and adding a little bit of noise to their paths could make the effect look calmer
A tiny bit of angular rotation to your circular plane might help it blend in with the prevailing, clockwise motion of the portal. The uv panning will probably still back-track the direction once in a while, but it’s worth trying!
Giving some clockwise orbital rotation to the sparkles could also help unify the motion
As an alternative to point 2, you could try setting up UV rotation, instead of panning. There’s a good discussion of the shader math required on the Unity forums . If you’re using a node based shader editor, they usually have a “Rotation” node that will do the math for you!
I still have a lot to learn, so take the above with a grain of salt.