Render Billboard Sprite on top of 3D Objects?

I'm creating a multiplayer split-screen retro fps game and am trying to make it so whenever a player shoots a wall, a billboarding shot-debris sprite instantiates at the point of impact.

Just like in the original doom game. (see below gif)

The problem is my current billboard shader doesn't render the debris sprite fully on top of the 3D wall objects at certain angles. It can be cut off as you can see in the below gif.

Adding ZTest Always to my shader does solve the overlap issue, but unfortunately, it makes it so the sprite can be seen through walls by other players in the game.

Not sure if adding Offset -1, -1 would help as I don't think it works with billboard shaders.

And I would like to avoid adding an actual offset from the wall since other players may see a gap between the sprite and the wall.

Any help is much appreciated. I'm just getting started with learning how to customize shaders. Here's the billboard shader code I'm using as well.

 Shader "Custom/Billboard"
 {
     Properties
     {
        _MainTex("Texture Image", 2D) = "white" {}
        _ScaleX("Scale X", Float) = 1.0
        _ScaleY("Scale Y", Float) = 1.0
     }
     SubShader
     {
         Tags {"Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent"}
         ZWrite Off
         Blend SrcAlpha OneMinusSrcAlpha
 
         Pass
         {
             CGPROGRAM
 
             #pragma vertex vert  
             #pragma fragment frag
 
             // User-specified uniforms            
             uniform sampler2D _MainTex;
             uniform float _ScaleX;
             uniform float _ScaleY;
 
             struct vertexInput
             {
                 float4 vertex : POSITION;
                 float4 tex : TEXCOORD0;
             };
             struct vertexOutput
             {
                 float4 pos : SV_POSITION;
                 float4 tex : TEXCOORD0;
             };
 
             vertexOutput vert(vertexInput input)
             {
                 vertexOutput output;
 
                 output.pos = mul(UNITY_MATRIX_P,
                 mul(UNITY_MATRIX_MV, float4(0.0, 0.0, 0.0, 1.0))
                 + float4(input.vertex.x, input.vertex.y, 0.0, 0.0)
                 * float4(_ScaleX, _ScaleY, 1.0, 1.0));
 
                 output.tex = input.tex;
 
                 return output;
             }
 
             float4 frag(vertexOutput input) : COLOR
             {
                 return tex2D(_MainTex, float2(input.tex.xy));
             }
 
             ENDCG
         }
     }
 }