Here is some CSS to apply at the layout level to resize the loading GIF. Currently, GIFs are cropped to ~150px^2. This code gives you full control. This website is helpful for helping to scale your image dimensions: Aspect Ratio Calculator (ARC)
/*Loading GIF */
#root-loading-icon > div{
width: 100%;
height: 100%;
display: block;
background-repeat: no-repeat;
background-position: center;
background-size: 1080px 608px; /* set GIF size */
}
#root-loading-icon > div{
position: relative; /* prevents fixed/absolute drift */
inset: auto; /* cancels top/right/bottom/left if applied */
}