PDF reflow is one of the major reasons I am using Koreader. The whole thing is very clever and works extremely fast given the limited nature of these devices.
> Is there an equivalent of DDWRT/OpenWRT but for TVs?
Get a used mini-pc, install Linux on it, and don't allow the TV to connect to any networks. This is a 50-75 dollar solution. Good if you are on a budget and are not interested in any wiz-bang features like HDR.
There are a few TV-dedicated Linux systems out there, like libreElEC.
Or get a more powerful system with a AMD GPU and install Bazzite on it. That way you get something like "SteamOS for your TV". Pairs nicely with controllers like 8BitDo.
It would be nice to have TVs as open as PCs, but the manufacturers and media companies are ran by dirtbags and would rather have victims then customers.
I have a 'smart tv'. I don't allow it to connect to any network.
The only really annoying thing about it is that noises from tv shows or the house sometimes triggers the voice recognition, which fails, and then you have to click through the error message.