I was disappointed with the automatic redact feature too, but saw that they just updated and added a graphical one also.

Agreed, you’re probably going to run into network bottlenecks before storage read times become an issue

Most TVs these days have a USB port for exactly this purpose, you can load media files up onto a flash drive and plug it in, then you should be able to browse the files and play it from there.

However, if you want to be able to play files hosted on your PC without having to copy them to a drive, you would have to set up a media server like Jellyfin on your PC and either buy or build a compatibility for your TV. Fire TV sticks or a Chromecast would work as cheap options to buy, or you could look into hosting a Kodi instance if you have spare hardware lying around.

There are really a ton of options, my above suggestions are only scratching the surface.

I believe Calibre has the ability to send books via the Kindle email address to get them on your device that way.