There are quite a number of AVRs that will transcode the HDMI connection to analog. However, it's possible the aspect ratio that ends up on the screen might not be acceptable, since the Roku has no controls for that. It all depends on what the AVR is capable of, but the more capable ones are going to be pricy. You would probably be better off trying a HDMI to analog converter box, as those are mostly under $50.
That said, the Roku Express+ has analog outputs (it was the last model with them), so you should be able to use that connection (instead of the HDMI) and get an acceptable picture. And that particular Roku does have aspect ratio control when using the analog outputs. And re-reading your last post I see you have tried the analog cable and perhaps it's defective.
But the problem with any of these solutions is you are still watching a standard def image. Even the best analog displays pale in comparison to even low cost flat panel HDTVs today.
Your Roku Express+ is 6-7 years old (depending on which model it is, there's two versions) and is really marginal for today's channels. It's lacking 4K/HDR, dual band WiFi, and has a much slower processor than the latest models. It's also really lacking in both operational memory and channel storage space. Really, I strongly suggest looking into a new Roku as well as a modern HDMI equipped display.
Dan
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee, just another user.
