Reality is in your own answer here. The Zen 2 3300X was just like a 4 core Zen 3. The main thing that change performance in both ADL->RPL and Zen 2- Zen 3 was cache changes. They are the same microarchitecture. Mucking with the cache doesn't change the pipelines or instruction width.
I've seen this marketing hype many times, where a 'new generation' CPU came out but was really same as the old one with more / faster cache and claimed to be a redesign. HP did the same thing with some of their PA-RISC chip releases, and I'd bet IBM did it with Power. Heck car makers do it all the time. New sheetmetal, same frame and powertrain.
Now I'm not saying it doesn't change performance - but it's not a new microarchitecture. Fact is, Zen 2 was starved by its cache, and Alder Lake had latency issues with its cache. These are all just evolutionary moves. for that matter - surprise - Zen 4 is as well.
But hey, don't believe me.
Believe Intel :
Details about Intel's next-generation cores revealed.
www.tomshardware.com