I’m not gonna lie….

[BB49]

Is this possibly the most annoying and redundant saying that has come from the other side of the pond? My DC (teens) are constantly saying it and I want to murder the originator of it.

Yes I hate it, I bought a car once and the seller kept saying 'i'm not gonna lie' as if they were doing me a favour.
IF THE BRAKES DON'T WORK THEN BLOODY WELL TELL ME STRAIGHT

I can’t stand “you’ve got this “

I don't think it is an American import. It seems too generic for that.

The phrase "I'm not going to lie" (or "I'm not gonna lie") does not have a specific, single origin place or time. Instead, it is an informal conversational marker that evolved from the older, more formal phrases like "to be honest" or "to tell you the truth".
The practice of using a preface to signal an honest or blunt statement has existed for a long time in English.
Modern Popularity: The specific phrasing "I'm not gonna lie" became a widespread, trendy verbal tic and general conversational filler, particularly gaining significant popularity among teenagers and young adults in the United States around the 2000s and 2010s. It often prefaces statements that aren't necessarily sensitive or critical, but rather an unvarnished opinion or admission, such as, "NGL, I liked that movie".
Internet Slang: The abbreviation NGL emerged and gained immense popularity through social media and online communication platforms in the late 2000s, further accelerating the phrase's use in everyday speech.
Ultimately, the phrase is a modern iteration of a common linguistic phenomenon: using discourse markers to emphasize sincerity or authenticity in communication.

Not gonna to lie, copied that from the computer

The exact phrase "not gonna lie" is probably an import from African American Vernacular English (AAVE) via US popular culture. However, the linguistic mechanism of emphasising your point by specifying that you're telling the truth (when there's no reason to think you would not do so by default) has long existed in Scottish English (“A’ll nae lie tae ye”, “A’m no lyin", "nae lie") and in English English ("if I'm honest ... ", "truth to tell...", "to be honest..." or the older - even back to Shakespeare - "I’ll tell thee true,” “I speak no lies,” etc.) and is also borne out via the common contemporary use of adjectives like "honestly", "truly", and "frankly".

I hate this too

Yes! Loathe it! Just say what you want to say directly.

Also, gonna, wanna, shoulda, coulda, and “like” inserted in to every spoken phrase.

Me too! It's a load of meaningless bollocks; and to me adds more pressure. It's lazy and cliched