He's scored against Barca, Madrid, Bayern, Dortmund (like 4 times in 3 games), Juventus (in the CL and from the halfway line in preseason), the PL elite, and basically every top team he's played against.
In that CL final season, Spurs wouldn't have even made it past the group stage without Kane's goals and assists. England wouldn't have made it out of their/our 2018 WC group without his goals, let alone the last 16 (which is actually pretty shocking). He also took England to the Nations League finals with great performances against Croatia and Spain.
He won Spurs a LC semifinal against Chelsea. He scored in an FA Cup semifinal against Chelsea, which Spurs proceeded to lose. He dragged Spurs through about half a dozen FA Cup ties, despite typically being only a desperate substitute in that competition (in his absence, Spurs have gone out of the cups to teams like Colchester and Norwich). He opened the scoring at the so-called "Battle of Stamford Bridge", which Spurs absolutely had to win to stay in PL contention. And that's just his story against Chelsea, leave alone his NLD heroics.
He's scored tons of important goals at key moments for club and country against every level of opposition. My point is that his opportunities to prove himself further have been limited by the quality of the teams he plays for rather than his own ability. Within the confines of what he's had the chance to do, he's done most of it. It's not his fault if he scores at a historic ratio but his defence keeps letting in more than he can score (or than anyone can realistically be expected to score).
Anyway, people like you are the reason I'm shitposting Kane stats. And there are just so many of them: all suggesting that Kane is utterly elite, a top-tier striker.