[ARA]

Интересно сработает ли это:

shader_type spatial;
render_mode unshaded;

uniform sampler2D Texture_0 : hint_albedo;
uniform sampler2D Texture_1 : hint_albedo;
varying flat vec2 uv_out;
varying flat vec2 uv_out2;

void vertex() {
    
    vec2 speed_0 = vec2(0.1, 0.02);
    vec2 speed_1 = vec2(-0.1, -0.02);
    
    vec2 uv_0 = TIME * speed_0;
    vec2 uv_1 = TIME * speed_1;
    
    uv_out = UV + uv_0;
    uv_out2 = UV + uv_1;
    
}

void fragment() {
        
    vec4 Tex_0 = texture(Texture_0, uv_out);
    vec4 Tex_1 = texture(Texture_1, uv_out2);
    
    vec4 Color = Tex_0 + Tex_1;
    
    ALBEDO = Color.rgb;
}

Вместо flat можешь попробовать
flat - The value is not interpolated
noperspective - The value is linearly interpolated in window-space
smooth - The value is interpolated in a perspective-correct fashion. This is the default