First, make sure you're using an 18 Gbps HDMI cable. Ignore any label that says 4K or other marketing nonsense. There's no such thing as a 4K HDMI cable.
I have never seen the menu settings in a TCL TV, but look in the settings for something labeled UHD Color, or some other similar setting, that is for the HDMI ports. It might say Enhanced Color, or something else like that. Unless those are set your HDMI port isn't HDCP 2.2/HDMI 2.0 compatible. And those are necessary for many devices to recognize a 4K/HDR display.
Dan Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.