Yes, it is factual. The M1 256 model uses a step up on the SSDs as well as using 2 x 128 / 2 “NAND” chips. On M2 256 there is 1 X 256 / 1 NAND chip. While The step up SSD model on M1 provides a modest + difference, it is the single NAND chip that makes a very substantial difference. Ultimately your r/w speeds will be substantially higher on M1 256 vs M2 256. With M2 512 (2 NAND chips) may be near the same though likely a bit slower than M1 256 due to that step up SSD.
To give credit where it’s due, I know this due to MaxTech on YT. It has been the point of all this. You can see their last video on it here (they literally said “this is our last video on the subject” all drama closed from here).
https://m.youtube.com/watch?v=H6Olqv5ChlQ
They’re generally fans of Apple but they were disappointed with the NAND issue and step down SSD. But it is important to note MaxTech uses Light Room video edits and exports for their daily use. That matters to them, and use it to stress test the machine. The average user is unlikely to see any performance degradation unless they are stressing the machine.
Bottom line, for an M series MBP 13, you probably made the right choice with M1.