Is there a restore symmetry plugin for 2.9? Or a function similar to it?

I’m basically altering a sims 4 face model, and I use proportional and mirror editing to reshape the features (Sculpt isn’t an option. Turns out glitchy).
Now, this works perfectly fine, but the mesh sims provides is ever so slightly asymmetrical, making it hard to shape without manually changing both sides at times; which can create a mess, especially for sensitive areas like eyes.
Deleting the vertices on one half, and mirroring the other half of the face is not an option, due to how the face will animate and function in game.

Is there a way I can easily get the vertices on one side of face to mirror the other side without removing any of them, or creating any new ones? Restore looked like it did this, but it doesn’t work for 2.9.

Okay, here goes.

In the Object Data Properties tab, there is the Shape Keys tab.

If you start with a Basis shape key and then add a New shape key, you can slide the value to 1.000 to display the shapekey.

Pressing the inverted carrot to get the menu, choose ‘New Shape from Mix’ to create a copy. Then, choose ‘Mirror Shapekey’. With both Shapekeys set to 1.000 to view, (if this is what you want) then you can press Alt-C and ‘convert’ to Mesh to apply the shapekeys and delete them from the stack.

I presume you’re talking about something like this, which doesn’t mirror the default vertexes, only the changes made to them; but even when I did follow the tut, it’s just a complete mess. My entire face inverts its self, and doesnt even mirror the changes made.

Okay, new line up, same problem.

With the object in Sculpt mode, go to the top by where the settings for symmetry are. Choose +x to -x or opposite of that, and press ‘symmetrize’ and it should work as you intend.

Let me know if you need screen shots.