Background image distorted in some blocks in mobile view

Site URL: https://www.biconsboutique.com/

*FYI this is on an 18+ site, nothing explicit shown but we are sellers of adult products*

i want to know how you can possibly mitigate the distortion to the background images in different blocks on mobile view. On my homepage I have blocks containing text, some containing links to social media etc. In desktop view the background image appears to maintain at constant size and appearance throughout all blocks. But when this is in mobile view, the background image distorts: on some blocks the pixel stars become really enlarged and on others they remain relatively consistent with the reduction in size of the content. I'm okay with coding and can apply this where necessary, but just can't find the resources online to suggest how to tackle this problem. Any help would be really appreciated.