Reinstalled Calibre in my new PC - can't convert books or send to device

Title. Recently, I upgraded from another computer, and as such, I had to reinstall every single piece of software, Calibre included.

Today I wanted to transfer some books, but I realized both the option to convert them and send them to device are greyed out. I have tried everything except doing a factory reset. I'm not sure what I've done wrong. I specificied the device to read epub files, but it's still greyed out.

Same as when you initially go through the startup process that you tell Calibre you'll use a Kindle paperwhite (in my case) the software will still have the options greyed out.

At this point I don't know what else to try, should I do a factory reset to my Kindle? I will of course lose everything, but at this point...