Already back in the 00s you could get a media player box, with a remote, that hooked to you TV and played video files from any share in your network or an HDD hooked up to it.
Nowadays you can get an Android TV media player box with Kodi on it (or you can install it), again with a remote and hooked to your TV to do the same as that 00s media player box but looks a lot more fancy.
Or instead of an Android TV you can get a Mini PC or older laptop, ideally with Linux, with an HDMI output which you connect to your TV, install Kodi on it and get a wireless air-mouse remote (if you get one with normal remote buttons rather than the stupid "for Google" ones, the buttons seamlessly integrate with Kodi so you don't really have to use the air-mouse stuff).
Alternativelly if you want to avoid Android but don't want to spend 150 bucks on a mini PC, you can get one of those System On A Board devices like one of the Orange Pi ones, put LibreElec on it (small Linux distro built around Kodi) and do the wireless remote thing with it.
The back end of any of this is either files on a NAS, on a share on a PC, a harddisk connected directly to the device or even something like Jellyfin running somewhere else (which can be outside your home network) or even any of the many IPTV services out there.
It has never been this easy to put together a hardware and software solution, entirely under your control - read: just as easy to use for corporate streaming services as for "personal" media - to watch media in your living room with the same convenience as purpose built devices for that, and it has never been this convenient to use or looked this good.