Dumb TV devices recommendations

[DeanoVIP]

Hey, could someone recommend me a HDMI device for my TVs.  I currently use a Chromecast HD Gen 3 which I like but it only supports H264 and same with my older Roku Express 3930 which I believe are the same.

So two questions:
1. Am I right in thinking that my server is transcoding everything to h264 if it is h265.  If this is the case do this cause my more load over the network?  I get the server has to do more work, but I'm trying to avoid buffering over WiFi.

2.  Can someone recommend some devices that will support h265 and atleast WiFi 5.

My theory is my furthest TV on the network struggles when media is transcoded. While it has good WiFi in the mesh some content it buffers a fair bit. Unfortunately wired is out the question.