That's not how base clock works. Base clock is not min clock. Base clock is what it's "guaranteed" to hit under sustained load if TDP is respected. It's the TDP clock. A 4ghz base clock CPU will still be far, far below that when idle.
I went from an 6700HQ (2.6 Ghz base) to a 10710U (1.1 Ghz base) and the difference is definitely there, and it's jarring enough to the point where I kind of regret it. It feels like a huge step backwards, despite the latter CPU being four generations ahead.
Isn't this completely down to the cpu frequency governor in the OS?
My impression was that this "stepping" is customisable, at least in linux, I regularly step my CPU manually even.
I'm not sure what Apple has here, but maybe it's not what you expect.
This does not seem to be the case for my i7-8565U nor my older m3-something. The 8565U for example feels just as snappy as my desktop i7-6700, except it’ll throttle after about 30s.