While I think your best solution is likely to get an hdmi splitter as suggested, I'm still unclear on how your other devices are connected to your receiver, tho.
FYI right now that input to the tv is component and composite, component for the video (3 rca cables on the left of the picture) and two composite cables (2.0, left & right channel inputs, the two rca cables on the right) for the audio.
The one end of the hdmi cord doesn't tell me a lot. If the other end is the dvd player then perhaps your dvd player is then connected to your avr for audio with an optical or coax digital cable to enable your avr to be supplied with 5.1 audio.
Similarly you can use an optical cable from your tv to your avr....but you may or may not get 5.1 audio this way; I looked in your tv manual briefly and while the optical out has settings for Dolby Digital, PCM or off. This doesn't mean that audio from an hdmi input, such as your Roku/Fire Stick, will come out 5.1 (quite a few tvs will only output 2.0 from such inputs, but may allow 5.1 from over-the-air reception). This is an optical cable
https://www.amazon.com/AmazonBasics-Digital-Optical-Audio-Toslink/dp/B00L3KO5WK?psc=1&SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-d-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B00L3KO5WK.
A photo of the back of your avr would be nice as well as the other devices to get a complete picture. Be careful with too-short cords as you move things around, stress on the connections isn't a good thing. Might want to get one of your tech savvy kids/grandkids to help out even with an hdmi splitter install....it's probably right up their alley.
Good luck!