How to set SD card as default storage?

Not sure if I'm doing something wrong, but I cannot figure out how to make the external SD card the default storage. Be it for downloads or data from apps, it's all saved on the internal one and I can't see a way to change it. Most answers I found on google are suggesting to change it in the settings (storage --> make SD card primary storage, which is not available) or in the aosp browser (not available either). :eek:

Any suggestions? Thanks!