I got that Costco 55C803 for a family member. As you know it's the same TV as the C807, but the Costco variant was on sale for $250 cheaper while at the same time providing free 4yr extended warranty. Only difference, the C803 is bundled with a RC280
TCL basic IR remote which has clackety buttons, easy to get blocked, and lacks the voice control, headphone jack and remote finder features (compared to the enhanced Wi-Fi remote).
But you can still pair the C803 with the RC126 TCL enhanced TV remote (Amazon $60)
-- or the RC135 Roku Enhanced Voice Remote ($30)
from 2017 Ultra if you don't need the mute button.
The C803 initially hides the UI menu that deals with Wi-Fi remotes, but it'll show up after the first boot-up pairing, or if you manually toggle it:Home x 5, FF, Play, RW, Play, FF-> "RF Remote Menu"-> "Enable full UI support for remote"
BTW the $30 RC135
"Enhanced Voice Remote" (from 2017 Ultra) can serve as a cheaper replacement for a RC126
) TCL Roku TV enhanced remote.
The TV controls, voice, headphone and remote finder all work. It just sacrifices the TCL remote's mute button for A/B gaming buttons (and a few other differences such as button shapes/placement, matte vs glossy front, flat vs rounded back, etc).
Or get the $20 RC127
"Streaming Stick Voice Remote" (from 2017 Stick) if you just need the TV buttons and voice commands. Ditto for the RC150
remote from the Stick+.
What's interesting is that once paired, these new remotes' power and volume buttons work on the Roku TV set via Wi-Fi instead of IR, just like the original TCL enhanced remote. IR not even an option in this case.