Tendulkar does and will always have more stature, due to his position in a huge Indian market when the game was becoming really big in the country.
His stature and legacy is only matched by a few players through history; Hobbs, Sobers, Bradman, Tendulkar, Viv and maybe Warne for me.
Lara also has a great legacy, but definitely not to the same degree. I am not going to talk about him much as for me he is below Sachin in terms and stature, test batting and ODI batting.
The more interesting debate is in terms of actual ability and performance. For me Smith’s dominance of series (home and away ashes, vs India in India), is above anyone of the modern era and the consistency that he scored runs at is unbelievable. He already has more greatness innings than Tendulkar and if he goes on to score 10k at 60+, with his current strong away record and performance against good attacks I will consider him better than Sachin as a pure test bat - obviously as an all format player Sachin will always be ahead of him, baring him doing something silly like averaging 60@100 in ODI’s for five years which he isn’t going to do.
As a test batsmen, Kohli is clearly below Sachin so far, especially given for me he is going to have a sharp decline due to how he plays outside his eyeline. If Kohli can repeat his overseas performance in SA, Eng and actually win, then maybe he can elevate himself to Sachin’s tier but for me that is unlikely.
In ODI’s Kohli needs a big WC to stand with Tendulkar, or at least a big final performance, which Tendulkar doesn’t have, to compensate for the disparity in their WC records. In both 2015 and 2019 Kohli came into the World Cup as the best batsmen in the world and was very good, but his performances did not match those of Tendulkar in his dominant world cups.
Basically, Tendulkar’s legacy will not be matched by a player from this generation, but Smith has a decent chance of being considered a better test batsmen. For me Kohli has an uphill climb to be considered better in either format.