sony ereader not visible in adobe digital editions

I bought an ebook that I would like to read on my old Sony PRS-T2. I have downloaded and installed Adobe Digital Editions, but my ereader doesn't show as a device.

I've read about this and online see the suggestion that I should connect ADE and my reader via Sony Libraries.

However, Sony stopped supporting this service since January 2023 so I am unable to make use of Sony Libraries.

Does anyone has a suggestion on houw to get this ebook onto my ereader?