Heya! Sorry, I would've added some links but I was on mobile and still am.
As I hinted at, this is mostly coming from anecdotal wisdom I've heard. The hardest evidence seems to be Apple's chips increasing more (10-20%) in GB6 vs GB5 when compared to how much other manufacturers such as QLC and INTL increased. As another comment said, GB5 is well known to be quite accurate with SPEC (industry standard), thus this discrepancy with GB6 and GB5 is a bit concerning.
Of course synthetics are always skewed (sometimes because a chipmaker tries, sometimes not), most famously Cinebench which has lost most credubility for favoring SIMD perf far too much.
Also might be worth it to check out the top comment to see an example of how a choice can bias syncthetics but not real-world.
Also might be worth it to check out the top comment to see an example of how a choice can bias syncthetics but not real-world.