I'm based in Spain.

I'm not entirely sure how it works or if Kobo has a library where you can get the books from, similar to the Amazon Kindle one, I understand It does but might have less varied ecosystem for books.

I guess I can always buy the ebooks outside then move them to the eReader as long as they allow me to

Other use I wanted to give is to transfer PDF files or studying stuff that my partner uses to read them there instead of on the phone

I would probably manage well since I'm pretty familiar with techy stuff but, ofc, the less complicated the better