Question TCL 55" backlighting problem ??

[TexasYankee]

I have a TCL 55S403 (Roku) - about 7 years old - problem is a dark screen (NOT AN ALL BLACK SCREEN) during nighttime scenes - most of the time, the TV picture is great - problem is just during night time scenes - I've tried different "Brightness" settings, and there's a slight difference, but not enough to make the night time scenes visable - I have the same problem on all of the streaming apps (Netflix, Prime, Hulu), and any of the Roku "channels", etc. l've read about replacing the LED backlighting strips - doing that that repair myself looks to be beyond my capabilities, maybe not even the real problem, and maybe not worth it when I can get a new TV for a few hundred more than the cost of the repair parts - does it sound like my problem is with the LED backlight strips, or something else? Given the technology in my 7 year old TV (see below), I'm wondering if a newer TV will have better technology to handle the dark night scenes??

TCL 55S403:

• 4K Ultra HD Resolution
• High Dynamic Range (HDR) Technology
• 4K Creative Pro upscaling engine
• 120Hz CMI effective refresh rate