Give a program access to all hard drives...?

I’m using the messenger signal. Somehow when I want to send files with it my second internal ssd drive is not shown in the file browser.
Outside of signal and from other programs in the Files I can use it perfectly.

any suggestions? Is it signals fault?

I do not know if Signal uses a built-in File Manager or uses an external File Manager. If it uses an internal one, it might not detect the other drives correctly.

There are some programs where in the built-in file manager, I have to go to / then /mnt to get to my drives each time (that’s where I mount my drives).

hm i also noticed that the main computer folder (I guess thats the root folder?) doesnt show all folders. Boot and data are missing for example