You could look into Intel Compute Sticks[0]. They're small Bay Trail (quad core Atom) PCs with a male HDMI and a USB port. They will run Linux well enough but it's a bit of a pain to get it installed since they've only for a single USB port. They used to be really cheap so they may still be. IIRC they've got full VP9 and h.264 High Profile hardware acceleration.

[0] https://www.intel.com/content/www/us/en/ark/products/series/...