The only way I've seen HDR content washed out is when watching it on a non-HDR set. Is your TCL a 1080 or 4K set? Since it has HDR settings, I must assume it's 4K and as such supports HDR. But as StreamerUser shows, you can disable HDR within the Netflix app itself.
As I'm not a Netflix user, I can't comment on how well they do HDR. But I watch HDR/Dolby Vision on the Disney app and it looks fantastic, as well as the 4K/HDR movies I've ripped to my media server. If it looks washed out, something somewhere is set wrong. And it might very well be on Netflix's side, not your TV.