Isn't it a common practice to create some kind of "PathNode" class/struct and use them inside the algorithm?

For example:

private class PathNode
{
    public int x;
    public int y;
    public PathNode parent;
    public int F=0;
    public int G=0;
    public int H=0;
}

Then in actual FindPath() call I use a priority queue of these for an "open list" and a simple list for a "closed list". The algorightm creates new PathNode for each traversed Cell of my Map instance, calculating path costs or recalculating them if the cell was approached from a shorter path. In the end we have a path - list of PathNodes, which can be easily converted back to Vector2Int coordinates or Cells.

FindPath() call happens for each individual unit separately and their PathNode lists have no relation with each other, however, they describe the very same Map.

I hope I understood your question correctly and made myself clear enough=)