It’s maybe a little hacky, but you can replace the default SVG pattern with a custom image with the help of CSS.
Example result
In the uploads section of your theme, you add the screenshot
and in the CSS tab of “edit code” you add
lowercase & replace spaces with hyphens
.theme-card.=THEME_NAME= .theme-card__image-wrapper svg {
display: none;
}
.theme-card.=THEME_NAME= .theme-card__image-wrapper {
background-image: url($=UPLOAD_NAME=);
background-size: cover;
background-position: center;
}
I hope this is enough to bring a little more relaxation to your inner Monk.

