Automated book grabbing is very hard imo. I’ve tried readarr and a bunch of other things. I settled on just manually downloading what I want and sending to kindle. There isn’t going to be a good automated setup until indexers get better for ebooks or readarr somehow adds support for irc downloads.

Second stremio. I use the torrentio addon without rd but always with vpns. It’s a backup for me for when my main nas goes down so I don’t want to pay for rd.

I’m not the guy you asked but I do the same thing. In the tailscale dashboard you can set up a default DNS for every device that is connected to your tailnet. They support nextdns and a couple other things. I have mine pointed to my personal adgaurd home server that is within my tailnet and it works great. I used nextdns for a while but didn’t want to pay for it. It also worked great with tailscale.

OpenBooks by Evan buss on GitHub. It’s an irc based downloader and I have been able to find even the most obscure stuff with it. At least so far.