If the effort is big enough it drains your life force. It happened to Luke Skywalker when he projected himself on Crait from Ach-too and to Ben Solo when he brought Rey back to life through the force.
Several Force powers had different demands in concentration and endurance than others, on behalf of the Force user. Continuous or excessive usage of the powers would have resulted in "Force fatigue" with several unwanted symptoms, both physical and mental.
The main reason for this is due to Kenobi's long stint in hiding. Again, Kenobi has been in hiding for around ten years, slowly diminishing his connection to the Force. While the Force, and people's abilities with it, are hard to define in Star Wars, it remains the case that the Force acts as any other skill does.
Although Luke was becoming sophisticated in some elements of the force, he wasn't strong enough or powerful enough to defeat the rancor by force projection alone. He had no weapons and nothing really to physically use against the rancor.
But one Jedi stands above the rest and needs to start getting recognized as the greatest Jedi who ever lived. That is none other than Obi-Wan Kenobi. While this saga is ultimately the story of the Skywalkers, Obi-Wan is arguably the best and most pure Jedi to ever come out of it.
Those who aren't killed have gone into hiding and can't communicate with each other. For ten years, Obi-Wan has been in hiding, can't communicate with any of his old comrades. He's living a pretty solitary life, he can't use the force. So, in a way, he's lost his faith.
Force lightning ability was not restricted to dark-siders. Jedi and other light-siders who were strong of will and character could learn this power without falling to the dark side—but its use was viewed as inherently corrupting, and most Jedi Councils forbade its use.
It's already well-established that Qui-Gon was incredibly strong with the Force. He continuously studied the ways of the Force and eventually learned enough about the Cosmic Force and the Living Force to unlock the secrets of eternal life.
However, unlike the Sith, who wish to live and hold their power for eternity, immortality through the Force is different. Qui-Gon knew it. He learned it from the Shaman of the Whills, who taught him that becoming a Force Ghost requires a person to be entirely selfless.
Qui-Gon Jinn was a respected, independent Jedi Master who first located and identified Anakin Skywalker as the Chosen One foretold in the Jedi Prophecy. Born on Coruscant circa 80 BBY (Before the Battle of Yavin), Qui-Gon trained as a Padawan under Jedi Master Count Dooku.
Most of us can withstand up to 4-6G. Fighter pilots can manage up to about 9G for a second or two. But sustained G-forces of even 6G would be fatal.
The Prime Jedi was an individual who became the first Jedi to ever use the Force. The Prime Jedi was also the founder of the Jedi Order. The Prime Jedi established the Order on the planet Ahch-To, around 25,025 BBY.
Vader relies on the complex life support system of his suit to survive and it happens to be very vulnerable to electrical discharges. So, if Vader ever had unleashed Force lightning, there's a good chance it would've caused his suit to short circuit, thus, killing him.
Darth Vader can not use force lighting, because of his severed arms. Robotic hands can't summon the force lighting.
It's likely Kylo never learned how to summon Force Lightning
He would teach and tell Kylo only what he wanted to, making sure that he stayed within limits and would certainly never get to the point of almost destroying him as Anakin did — therefore neglecting training in Force lightning.
As One of the Last Jedi, Kenobi Kept a Low Profile
With the Jedi all but wiped out at the end of Revenge of the Sith, any use of the Force draws the wrong kind of attention. Darth Vader and his Inquisitors can detect the tremors that it entails, which they use to hunt down the last remaining Jedi.
The Force: Kenobi was extremely powerful, and had an extremely strong connection to the Force, and was one of the most powerful force users of his time. Though Kenobi did focus largely on Lightsaber combat, he was also very skilled and powerful in use of the Force.
The Star Wars universe is home to many force-sensitive characters, and not all of them are Jedi or Sith. From Grogu to Finn, here are 10 examples. Typically, force-sensitive characters tend to either become Jedi or turn to the Dark Side. Sometimes, even both.
Within the Star Wars Legends continuity, Yoda's Jedi instructor was N'Kata Del Gormo, a Hysalrian Jedi Master, according to an in-universe legend.
Obi-Wan Kenobi
Through it all, Obi-Wan reveals himself to be one of the very best examples of what a Jedi Knight should be: selfless, kind, and willing to do whatever it takes to protect those in need.
Yoda found himself overpowered in battle against Darth Sidious, who would become Emperor Palpatine, but his wise retreat gave him time to mentor a new hope before ultimately succumbing to old age and passing into the Living Force on the planet Dagobah.