"I don't want to have to pore over review articles and youtube videos to figure out how many performance grades correspond to how many generational jumps and cross reference to older generations. I just don't."
If they named things properly and wouldn't mix generations within a single generational series marketing campaign (5xxx series), you wouldn't have to - as a consumer, if you wanted to buy the best, you would buy the 5000 series. They would still carry 4xxx stock - if you wanted something at a different price point, you'd buy the 4xxx series.
AMD's choice to mix generations within the same series makes things more confusing, not less confusing.
That's only true if generations don't overlap in performance. If they do overlap, either the company "ports" the old products into the new lineup or you're in for considerable homework.
What is the point then in up-branding a chip with identical performance that spans two different process generations?
Do the two different generations have different TDP envelopes? I though the 5xxx and 4xxx series both use Vega - what is the appreciable product difference between Zen 2 and Zen 3 if the performance/TDP/graphics performance is the same?
I think you are kinda answering your own question here? the difference between Zen 2 and Zen 3 is that they are different architectures. there may not be an appreciable product difference between a mid/high bin Zen 2 part and a low/mid bin Zen 3 part. this is why we have SKUs; they take a spreadsheet worth of details and compress them into a rough total ordering of price/performance.
the point is that it's annoying to compare 4000 series parts against 5000 series parts to figure out what is the best budget AMD CPU. outside of enthusiast circles, no one cares about being on the latest architecture. they care about what is currently the best performing part within their budget.