It’s possible via the settings of the attribute, so please navigate to Products -> Attributes -> edit the attribute that you want to make bigger and change the size here: https://prnt.sc/28D4Ms43prg0
There’s no size option available for an “image swatch” type. Please see my attachment. I’m not using colour swatches. I’m using a .png image. The size is set to 55x55px and there is no option to change it.
Please, confirm the permission for plugins deactivation, and switching to the parent/default theme. As soon as we complete the testing we will enable it all back, however, You would better make the full backup of your site.
Also, please send me a link to the product with such swatches with images.