I can't answer for the Shining Path/Taliban (the latter would infringe upon the 20 year rule if we're talking about Afghanistan post-2001).

However, I can speak about the influence of the popularity of Maoist guerrilla/insurgent tactics on a general level. Essentially, Mao's tactics, developed during his experiences with the nascent Red Army fighting the Chinese Civil War and particularly during the 'Long March' period, were the culmination of nearly a century's growth in guerrilla strategy. For an immediate predecessor, I would recommend taking a look at T. E. Lawrence's writings on the practical workings of a guerrilla force - he describes precisely how one must "be like air", attacking and disappearing, to continually weaken a larger opponent without actually engaging them in a conventional pitched battle.

These tactics are specifically developed for any force which would otherwise be unable to defeat their larger, conventional enemy. They advocate what Mao terms the "strategic defensive", in that they attack constantly whilst never exposing their own troops to real risk. Such a strategy has been perfect for most 'revolutionary' forces in the latter half of the 20th century; these are generally small sides, fighting against an established state. And, crucially, they have an ideological grounding, meaning that the fighters will fight for their beliefs and thus endure the incredible hardships guerrilla wars necessitate. To put it simply, Guerrilla tactics allow them to greatly even the odds.

The reason Mao's doctrines specifically seem to have been so widely spread (a claim you've made that I'll just run with, though I can't find direct evidence for it) is twofold. Firstly, Mao's 'Red Book' and 'On Guerrilla Warfare' are some of the most widespread, easily accessible and well known document which detail how guerrilla wars may be waged. This fame, as it were, makes them an easy choice for a would-be guerrilla. Take the Mujahideen in Afghanistan against the USSR, for example. Their tactics were directly based upon these documents, as some of the unit commanders apparently had read Mao and Lawrence - Max Boot's Invisible Armies is a good text for this. Secondly, the fact that Mao's tactics were also bundled up together with his ideology gave them a particular appeal. If you were a Maoist rebel group, you would naturally veer towards his doctrines. Hence the tactics used by the Guerrillas in the Malayan Emergency (covered excellently by Komer), the Viet Cong (McMahon) and the Naxalites in India.

That turned out to be pretty long. Hope it's what you were looking for. On mobile, so apologies for any spelling/word choice mistakes

Adding onto this, I read a book in which Ethiopian insurgents traveled to China for training. Was it common for Maoist China to train guerillas? How did the country make contact with the insurgents in the first place?

May I ask what your source is on the Taliban using Maoist guerilla tactics, OP?

I'm genuinely curious on this. Thanks.

As an additional question, what even are "maoist guerrilla warfare" tactics? What is its doctrine strategically and tactically? Is it executed in a similar fashion among its adherents, or did/are communist guerrillas just call/calling how they fought "maoist" for propaganda or political purposes?