Having already configured a VLC-powered Google TV configuration with USB hard drives for a relative without the router or download speed needed for reliable streaming, I'm now trying to configure a similar setup for another relative with a non-smart TV and an even slower download speed.
The only requirements for such a device would be the ability to be controlled entirely with a remote, a USB-A or USB-C port compatible with USB hubs and media storage devices, and the reliable playback of videos of assorted codecs and file extensions. As Roku, FireTV, and Android/Google TV streaming sticks tend to be plastered with ads as a means of promoting content within their ecosystems, an alternative HDMI device that minimizes the number of button presses between turning on the TV and and reaching the navigation menu for videos on attached USB storage devices would be preferred.
I'd recommend a Raspberry pi running Libreelec. Its Kodi so has a great UI with no ads or tracking, supports HDMI-CEC so you can control it with your TV's own remote (on most models) and I haven't found a video codec it can't handle. Also if you decide to move to a NAS or streaming for your videos in the future it supports that as well.
Any model of pi should be able to handle video playback from USB but older ones obviously can't handle 4k. Also a pi can't power a mechanical USB drive so if that's what you're using you'd either need them to have their own power supply or use a powered USB hub.
One like this could be used to power the pi and drives at the same time: https://www.amazon.co.uk/Anker-PowerIQ-Charging-Macbook-Surface-7-Ports-3/dp/B00VE4UJD4/ref=mp_s_a_1_1?crid=2SJ87KGXVYOFK&keywords=anker+usb+hub+powered+3.0&qid=1696764826&sprefix=anker+usb+hub+powered+3.0%2Caps%2C884&sr=8-1