If you’re referring to Chromecast with Google tv, than there is absolutely an app! Give it another shot!

Sorry I can’t help with your question, but I wanted to ask what features you feel Jellyfin is missing that is keeping you on Plex? I’ve made the switch, and actually like Jellyfin better.

Just went through this myself and settled on DIY build. Someone recommended this video, and I followed it very closely. The built was so easy and less expensive than off the shelf. I installed TrueNAS on it and couldn’t be happier.

https://www.youtube.com/watch?v=vjDoQA4C22c