Luke is the Last Jedi of the old order. Luke was trained by Yoda and Obi Wan - two of the final remaining Jedi Masters from the old order. Luke is the Last Jedi to be trained under the old principles and doctrines of the old order before he begins his new order.
The opening crawl of Star Wars: The Force Awakens referred to Luke as "the last Jedi." That was the title of the film's sequel, with director Rian Johnson confirming that the title of the film indeed referred to him (via Polygon).
Yoda considers Luke to be the last Jedi because he adheres strictly to the Jedi Code and does not accept unconventional training methods like those used by the "Bokken Jedi." Yoda believes that the "Bokken Jedi" have deviated from the path of the light and are heading closer to the dark side due to their aggression.
Following Palpatine's final defeat and her own resurrection, Rey adopts the name Rey Skywalker to honor her mentors and their family legacy and renounce her lineage. As the last remaining Jedi, she makes it her mission to rebuild the Jedi Order.
This mystery was especially prevalent in Star Wars: The Force Awakens, but The Last Jedi overcorrected it by claiming Rey is not related to any established original trilogy Star Wars characters. Then The Rise of Skywalker revealed, in an out-of-left-field retcon, that Rey is the granddaughter of Emperor Palpatine.
Admittedly, Rey skills couldn't possibly be as developed as Anakin's or Luke's. Nevertheless, considering how fast of a learner she is, and how unique the powers she possesses are, it's not a stretch to say that Rey could be a more powerful Jedi than Anakin and Luke Skywalker.
Even without this consideration, however, it's possible to find some in-universe reasons why Yoda referred to Luke as the last Jedi despite Ahsoka and Ezra, both people Yoda knew, being still alive.
It was believed that Grogu would eventually become a victim of Kylo Ren's destruction of Luke's Jedi Order. However, The Book of Boba Fett revealed that Grogu chose to follow the Way of the Mandalorian rather than become a Jedi, sparing him from Kylo Ren's wrath.
Anakin Skywalker carried this blue-bladed Jedi weapon throughout the Clone Wars. After dueling his former apprentice on Mustafar, Obi-Wan Kenobi took Anakin's lightsaber and kept it on Tatooine for nearly two decades. He gave it to Luke Skywalker, who lost it when Darth Vader struck off his son's hand in Cloud City.
However, astute fans notice the slight change in his facial features, especially between A New Hope and The Empire Strikes Back, which turned out to be due to a car accident that nearly sidelined his career just as it took off.
Rey is a palpatine and they planning to have her be the granddaughter of Obi wans younger brother from Stujohn so Rey is not a skywalker or biologically related to them. Although She is connected to the skywalker family through her grandfather Palpatine and her great uncle Obi wan Kenobi .
According to Imperial Estimates in Star Wars Inside #87, only about 100 of the Jedi survived Order 66. Most were subsequently hunted down and killed in the years following the Great Jedi Purge.
In The Rise of Kylo Ren comic series, it's shown that three of Luke's students confronted Kylo and chased him across the galaxy. Named Hennix, Tai and Veo, each of these pupils left before Luke woke up, and ended up being killed by the First Order shortly after.
So cute, so interesting, so compelling. So familiar and yet so new." Favreau has clarified that Grogu is not a younger version of Yoda himself, but has declined to comment upon whether he is related to Yoda or otherwise connected to him.
While fans don't know the state of Grogu's well-being in the sequel trilogy, his ties to Mandalore might explain why Kylo Ren doesn't kill him. It's likely Grogu stays with Din Djarin and the Mandalorians, and never returns to embark on his training with Luke.
After the Battle of Endor, Leia trained as a Jedi with Luke, but left the Jedi path after sensing it would result in the death of her son. She returned to the political arena, where the New Republic had reached an uneasy peace with the remnants of the Galactic Empire.
Yoda cryptically responded, "No, there is another." While some fans would make careers out of writing possible futures for these characters years later, many sitting in the theaters at that time had no idea what that quote implied. Now, fans know that Yoda was referring to Leia Organa.
Darth Vader didn't learn he had a daughter until Return of the Jedi, when he stood before Emperor Palpatine. The Emperor's power probed Luke's mind, attempting to goad him to fall to the dark side, and he discovered Leia's existence. "Sister," the Emperor taunted.
Kylo lost to Rey in TFA because he was heavily wounded and was holding back against her due to Snoke's request that he bring her back to him alive. He is also stated by Palpatine in the Secrets of the Sith book to be “equally as powerful as a real Sith despite not being one”.
Kylo Ren is not weak, his potential is certainly as high as any of the Skywalker lineage, but I believe he simply has a misunderstanding of how the Force works, and because of this misunderstanding, he has made himself weaker.
This caused him to attempt to assassinate him in his sleep. Needless to say, Kylo Ren is almost definitely a significant threat. However, we cannot definitively say that he is more powerful than Luke. Kylo's powers are vast but they are still highly unbalanced and difficult to control.
