Not irrelevent...(your spelling...)
You asked how to solve the issue. There are numerous ways to solve the issue. Using a soundbar...are correctly using an AVR.
And you are the one who said....first...
"Let's start with the TV with no speakers"...then changed to...
"Let's start with the TV...
To solve the issue with this particular TV...
I suggest a self-powered soundbar. I have, currently, 7 TVs and a projector. None of those are "on their own". Why?
TV audio....sucks.
I have 4 "theatres"(living room, actual theatre, office* and master bedroom).
The others all have a BA TVee25...
By the way...the area I highlighted and italics...to me says...
The TV, itself, has no speakers...ergo there must be an exterior source. Some of us use our phones, via the app, while working. We don't have time to search your TV. (and it is a B...not an 8, and the P7FXZC is irrelevent)