Why not just use qbittorrent? Has RSS, has search in the client, has paths based off categories...
I currently use the official Web UI in an isolated Chromium instance and made an automatic log in page so that I don't have to type in the password every single time I open it.
I add torrents to the qBittorrent instance using a Firefox addon. It's all a bit jank.
I started some work to make my own qBittorrent client for desktop; I don't care about mobile that much.
Otherwise there’s qui for qb which, while still a webui, is great.
No proper client/daemon (thus core/GUI, code is Qt-ware) separation with a clean transmission-like RPC.