### Godot version

v4.2.beta1.official [b1371806a]

### System information

Ubuntu 22.04.3 LTS 22.04 - X11 - GLES3 (Compatibility) - AMD Radeon RX 560 Series (polaris11, LLVM 15.0.7, DRM 3.42, 5.15.0-88-generic) () - AMD Ryzen 3 1200 Quad-Core Processor (4 Threads)

### Issue description

![image](https://github.com/godotengine/godot/assets/1330325/7a986599-5a68-42a4-beb1-5d3b4bf7db6b)
![image](https://github.com/godotengine/godot/assets/1330325/e8b8546b-b47b-4add-9567-7f70709ab03c)

Culling 3D goes bellow 60 fps even with just about 50 simple animated models. With v4.2.dev6.official [57a6813bb] many more models can be spawned without fps drop. However, both versions do show high cpu usage for culling 3D. Without animations there's barely any usage.

### Steps to reproduce

Spawn models with animation with the Compatibility renderer.

### Minimal reproduction project

[CullMRP.zip](https://github.com/godotengine/godot/files/13400514/CullMRP.zip)

bv.x = v.r;
			bv.y = v.g;
			bv.z = v.b;
			bv.w = v.a;
			GlobalShaderUniforms::Value &bv_linear = global_shader_uniforms.buffer_values[p_index + 1];
			
			bv_linear.x = v.r;
			bv_linear.y = v.g;
			bv_linear.z = v.b;
			bv_linear.w = v.a;
		} break;
		case RS::GLOBAL_VAR_TYPE_RECT2: {
			GlobalShaderUniforms::Value &bv = global_shader_uniforms.buffer_values[p_index];
			Rect2 v = p_value;
			bv.x = v.position.x;
			bv.y = v.position.y;
			bv.z = v.size.x;
			bv.w = v.size.y;
		} break;
		case RS::GLOBAL_VAR_TYPE_MAT2: {
			GlobalShaderUniforms::Value *bv = &global_shader_uniforms.buffer_values[p_index];
			Vector<float> m2 = p_value;
			if (m2.size() < 4) {
				m2.resize(4);
			}
			bv[0].x = m2[0];
			bv[0].y = m2[1];
			bv[0].z = 0;
			bv[0].w = 0;
			bv[1].x = m2[2];