### 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)

ERR_FAIL_COND(global_shader_uniforms.variables.has(p_name));
	GlobalShaderUniforms::Variable gv;
	gv.type = p_type;
	gv.value = p_value;
	gv.buffer_index = -1;
	if (p_type >= RS::GLOBAL_VAR_TYPE_SAMPLER2D) {
		
		global_shader_uniforms.must_update_texture_materials = true; 
	} else {
		gv.buffer_elements = 1;
		if (p_type == RS::GLOBAL_VAR_TYPE_COLOR || p_type == RS::GLOBAL_VAR_TYPE_MAT2) {
			
			gv.buffer_elements = 2;
		}
		if (p_type == RS::GLOBAL_VAR_TYPE_MAT3 || p_type == RS::GLOBAL_VAR_TYPE_TRANSFORM_2D) {
			
			gv.buffer_elements = 3;
		}
		if (p_type == RS::GLOBAL_VAR_TYPE_MAT4 || p_type == RS::GLOBAL_VAR_TYPE_TRANSFORM) {
			
			gv.buffer_elements = 4;
		}
		
		gv.buffer_index = _global_shader_uniform_allocate(gv.buffer_elements);
		ERR_FAIL_COND_MSG(gv.buffer_index < 0, vformat("Failed allocating global variable '%s' out of buffer memory. Consider increasing it in the Project Settings.", String(p_name)));
		global_shader_uniforms.buffer_usage[gv.buffer_index].elements = gv.buffer_elements;
		_global_shader_uniform_store_in_buffer(gv.buffer_index, gv.type, gv.value);