What is the equivalent in English of the French "pipotron", which refers to meaningless filler content that looks like it was written by a bot?

Given your description of the second meaning of pipotron, it would seem to be a nearly exact match for technobabble.

There is the word doublespeak, which Lexico gives as

doublespeak
_NOUN

Deliberately euphemistic, ambiguous, or obscure language.

The art of political doublespeak
We need candidates armed with insight, not condescending doublespeak
That guy has doublespeak down to an art form, like really good poetry

Sounds like a buzzword:

an important-sounding usually technical word or phrase often of little meaning used chiefly to impress laymen — MW

There is no automatically generated aspect to this, but the term Markov Chain may be of interest as it is a way to generate something that almost sounds like something a person would say. (Though I doubt many people will be familiar with the term.) See for example these quotes:

Reads like a markov-chain- generated series of buzzwords. — lukaseder on Reddit

LinkedIn is basically a Markov chain generated from a Google search for “buzzword”. — I am Developer on Twitter

This is a business buzzword (or buzz-phrase) generator based on Markov chains. — Hodapp87 on GitHub

One possibility is word salad. While it originally referred specifically to confused language indicative of mental illness, it’s now pretty widely used to any speech or writing that is incoherent to the point of meaninglessness. This blog post at Merriam-Webster has a discussion and some examples.

If you are looking to describe drivel in general, such as a politician or salesperson would use, then technobabble does not fit, as it is specifically restricted to drivel that uses tech buzzwords. Word salad is more general and refers to drivel in any context, including tech.

Of course drivel itself might meet your needs too.

Randomly constructed text typically used for design mockups is Lorem Ipsum, though this specifically refers to pseudo-latin text starting with "Lorem ipsum dolor sit amet...". This seems similar in use to your French pipotron based on your explanation.

see: https://www.lipsum.com/

The term I usually hear used for this is marketing copy (as in, ‘this sounds like marketing copy’).

This uses a slightly less well known meaning of the noun ‘copy’ (not even found in some dictionaries) which is roughly synonymous with ‘published text’. The term as a whole formally refers to the written materials used by the marketing department of a large corporation (as distinguished from things like technical documentation), and has come in some places to be used in a pejorative sense to refer to text that has a similar writing style to what is stereotypically associated with such material (that is, generally focused solely on sounding impressive without actually saying anything useful, and possibly only accurate in certain contexts).

A lot of the stuff posted online by people trying to convince the world to use blockchain technology to solve everything is an example of the type of writing, often using an absurd number of words to try and convey the argument that ‘it’s cool so you should use it’.

A couple of other words you might consider, though not necessarily related to technobabble (which is probably what I would use) are:

yada yada: Boring or empty talk.

Spiel: To talk voluably or extravagantly.

I'll also mention for fun:

Lorem Ipsum: pseudo-Latin text used in printing and website design in order to emphasise design elements over content.

This one doesn't exactly match what you want, but it is frequently used in a technical setting as meaningless text. However, it is deliberately meaningless, your pipotron sounds to me to be accidentally meaningless.

So this isn't a perfect answer to your question - I'd go with technobabble - but some fun words for you to think about.

I vote for the noun "waffle", derived from the verb "to waffle", as in when one "continues to waffle on" about a topic.

From Wiktionary:

• (verb) to speak or write evasively or vaguely.
• (noun) (Often lengthy) speech or writing that is evasive or vague, or pretentious. — "This interesting point seems to get lost a little within a lot of self-important waffle."

Merriam–Webster offers the definition:

(noun) empty or pretentious words; tripe.

I use and have often seen the word blurb used in this context. Marketing Blurb is basically decorative text with a technical ambience thrown up onto webpages. It is often completely devoid of informative content and more about giving extra marketing substance and context to the main features, images and links.

This is specifically in the context of marketing text. Your later paragraph on deceptive political bamboozlement is something else

I think the English word that fits here might be:

Bafflegab: Incomprehensible or pretentious language, especially bureaucratic jargon.

Or, as originally defined: "Multiloquence characterised by a consummate interfusion of circumlocution and other familiar manifestations of abstruse expatiation commonly utilised for promulgations implementing procrustean determinations by governmental bodies."

This isn't an acknowledged English word, but to address the important aspect in the question about the text needing to be, or appear, automatically-generated, how about using the prefix "robo"?

So one might feel inclined to say something like "robobabble".

A fluff piece. Typically a humorous report aimed at a humorous break of pace, after a succession of serious pieces.

The padding would apply,

unnecessary words or information added to a speech or piece of writing

• It could have been an interesting essay, but there was too much padding.

I've used it many times in relation to the content of technical reports or corporate documents.

Sounds like gobbledygook to me

Language or jargon, especially in bureaucratic or official contexts, which is pretentious, long-winded, or specialized to the point of being unintelligible to the general public; nonsense, gibberish (OED).

1944 M. Maverick in N.Y. Times Mag. 21 May 11/1
Just before Pearl Harbor, I..got my baptism under ‘gobbledygook’..its definition: talk or writing which is long, pompous, vague, involved, usually with Latinized words.