True, but not sure how often CPUs are operating at Base Clock - chances are they are either below that (between Minimum and Base Clock) or in Turbo Boost and the Turbo Boost speeds are pretty close to the 125W models, but likely with fairly lower TDPs so they may be able to get closer to Max Clock.
And the Comet Lake H i9-10980HK is 2.4GHz vs. 2.8GHz Base Clock for the i9-10900 so arguably it is better to stay with a 65W Comet Lake S desktop CPU than a 65W Comet Lake H mobile CPU.
Comet Lake H i9-10980HK has a TDP-up 65w mode which has a base clock of 3.1GHz. Added to that it's also a BGA chip which would be perfect for a Mac mini and would give it an amazing 8 cores, 16 threads.
The only downside is the price from Intel, but what if Apple were moving all iMacs and all Mac minis to the same CPU as the Macbook PPro 16"? Economies of scale could come in as could sharing motherboard chipsets etc.
For the mini an i9-10900 65w CPU is around $140 cheaper and has 2 extra cores (4 extra threads) but isn't guaranteed to come in a BGA package and each core has a slower base clock and marginally lower turbo frequency.
Of course, we know that these CPUs could be space heaters and going for a 45w TDP CPU all round gives more heat headroom in a Mini - and maybe a smaller enclosure of a future iMac.
If you think about it, AMD's RDNA2 Big Navi could help fill some of that performance gap for video editors next year.
Let's not forget that this redesign that everyone is clinging onto 'smaller bezels' for could be a serious enough change to get the iMac renamed so it can come with all SSD in a smaller enclosure. And at that point Comet Lake H might well be adequate if Apple allow 'Pro Mode' to spin up a cooling fan for more performance at the cost of noise.
That's all moot of course, if Apple decide that the iMac must have 4 RAM slots in the 27" iMac.