"Up to 20-30% faster" or "20-30% faster than M1 released in November 2020. In almost the exact time frame AMD went from Zen3 -> Zen 5 (so one less generation) with a total gain of ~34% multicore and ~59% multicore gain. Intel went from ~10900k to ~14900k for a total of 76% single core and 128% multicore gain (i.e. more than double).
Two disclaimers before the conclusion: This is just from one lazy benchmark (Geekbench 6) and of the high performing model. That doesn't necessarily tell the whole story on both accounts, but it at least gives some context around general trends. E.g. passmark is going to say the differences on Intel are a little smaller, comparisons between Max and non-Max generations confuse multi core growth, and changes in low-mid market chips may follow a different slope than the high end products. Also there are other considerations like "and what about integrated graphics performance, which eats up a huge amount of die space and power budget?"
Anyways, my conclusion is that Apple is doing reasonably well with generational improvements vs the competition. Maybe not the absolute best, but not the worst. Being on top in the single core realm with a mobile passively cooled device makes equivalent gains all the more difficult but they're still doing it. Apple may be a victim of its own success in that the M1 from 2020 is still such a performance powerhouse that a 50% gain 4 generations later just isn't that interesting whereas with Intel a catchup of ~doubling multicore performance in the same time seems more impressive especially when M*'s story isn't as tantalizing on that half of things.