I was having a very similar problem, but was able to adjust the wrapper for the text using this group of code:
@media only screen and (max-width: 480px) {
#block-ID // You'll need to find this...
.image-block-outer-wrapper.combination-animation-slide-up.animation-loaded.sqs-text-ready .sqs-dynamic-text-container {
opacity: 1;
transform: matrix(1,0,0,1,0,0);
}
An easy way to find the #block-ID is using the tool "Squarespace Collection/Block Identifier" (a Google Chrome Extension). This will then only target that image collage block. Then to adjust the position, change the matrix values to your desired result!
Hope that helps!