Universal remote control

Hello,
Normally the brand "Dual" is not on the list of compatible televisions.

http://www.groupe-normand.com/Fiche.php?superfam=SUPF15&sousfam=F038&ref=009535

--
The enemy is stupid: he thinks we are the enemy when it is him!
Pierre Desproges

Hello,
Before buying a so-called "universal" remote, you need to ensure compatibility. However, for this one it is specified in the description: "The brands that are 100% compatible are Sony, Samsung, LG, Philips, and Panasonic."
So try these 5 options
Press and hold the following buttons for more than 5 seconds and wait for the LED to blink three times, then release
-Power and Vol +
Then
-Power and Vol -
-Power and P-
-Power and P+
-Power and up arrow

What is the complete reference of your TV?

I call a spade a spade *
     *in French in the text

See this:
https://www.telecommande-express.com/tv/telecommande+ONE+FOR+ALL+:+URC7140?deviceName=ONE+FOR+ALL+DL55UHD002&old=1

--
I call a spade a spade *
*in French in the text