First of all your hair looks os healthy and strong. love t see hair like this. <3
Second, please wash your air with lukewarm water and sulphate-free shampoos to make sure the pigments won't fade.
That is my profesh advice for maintenance. ;)
About the product you are searching for why not try my brand Evilhair? We have some pretty ace ColorConditioners + ColoShampoos that I personally developed. I made them in the salon for my clients at first, the ones with vivid hair who wish to maintain the color vibrancy at home.
I think Crimson Red would be perfect for you since it is a burgundy tone with lots of violets and red that makes for a nice deep not to flashy red.Oh and GO Red ColorShampoo will prevent pigment faiding, try that one too.
I can set you up with a discount and also Im available to give advice, you can drop me a dm if you wish ;)
Cheers
Naya