Mirror clothing correctly in blender Can anyone help please?

Hi. There is the left and the right side of the body, which move independently from each, so weights must be re-done. With how morphing works in ts4, you must also mirror uv_1.
Do it like this:
- select the strap in edit mode;
- press Shift D, then Enter;
- Mesh -Mirror - X axis;
- Mesh - Normals - flip normals;
- P - selection to separate this strap;
- select the strap, add data transfer;
- choose the garment (from which you separated the strap) as Source object;
- enable Vertex data, then Vertex groups, choose Nearest face interpolated;
- enable Face corner data, then UVs, then uv_1, then Nearest face interpolated;
- apply;

- with the strap selected, switch to Edit mode, select everything(important);
- If using blender 2.76-2.79, 3.6.1, Tolls - Weights tools - Clean with All groups, then Likit total

- if using other versions, just Mesh - Weights - Limit total
- then just join the strap back to your garment

P is a hotkey for separation. Once your strap mesh is selected, press P and choose "by selection"

- switch to edit mode;
- enable sync in uv editor;
- press B, click and drag to select uvs of the strap;
- in 3d view press P, choose Separate;
- rename the separated mesh to Strap, and the other one to Torso;
- select the separated strap, switch to Edit mode again;
- change pivot to 3d cursor;
- select everything with A, Mesh - Mirror - X global;
- Mesh - Normals - Flip normals;

- select uv_1, change pivot to 2D cursor, select everything with A, UV - Miror - X axis;

- select Torso, then Shift-select the strap, switch to Weight paint, click on Transfer weights;