The loading bar is from Windows 11 and is almost like Google’s flat loading bar.
If not, I’ll kindly go my way to do this myself, but I rather ask first, before suffering on my own haha
Use tweening to get that smooth effect, then use a loading bar parented under a larger frame. Then make a loop which makes the bar tween, then sets it back to the original position so it looks something like this:
Then make the big frame transparent and turn on ClipsDescendants so it cuts off and then you have the final product