While it is to a degree true, it is also worth noting that the stockfish vs alphazero matches did get criticism for various reasons.
The one I remember most was that alphazero was running on a supercomputer, while it's opponents didn't get that luxury. This is said to be why alphazero didn't make it far when put on similar hardware as other ais.
The other criticism I remember was from stockfish's dev saying that the settings they have for stockfish where suboptimal, most notably they had a set 1 minute think time per turn. This is apparently not how stockfish works, because like a human player it will also calculate on which turns it will spend its time thinking.
So while alphazero may very well be better, there's not really a way to confirm this with these matches sadly. The matches whet still helpful to the chess community, though. Definitely still worth checking out