When ever I've built a new desktop I've always gone near the top performance with some consideration given to cache and power consumption (remember when peeps cared about that? lol).
From dual pentium pros to my current desktop - Xeon E3-1245 v3 @ 3.40GHz built with 32 GB top end ram in late 2012 which has only recently started to feel a little pokey, I think largely due to cpu security mitigations added to Windows over the years.
So that extra few hundred up front gets me many years extra on the backend.
I think people overestimate the value of a little bump in performance. I recently built a gaming PC with a 9700X. The 9800X3D is drastically more popular, for an 18% performance bump on benchmarks but double the power draw. I rarely peg my CPU, but I am always drawing power.
Higher power draw means it runs hotter, and it stresses the power supply and cooling systems more. I'd rather go a little more modest for a system that's likely to wear out much, much slower.
Is it really 2x or is it 2x at max load ? Since, as you say, you're not peggig the CPU - would be interesting to compare power usage on a task basis and the duration. Could be that the 3D cache is really adding that much overhead even to idle CPU.
Anyway I've never regretted buying a faster CPU (GPU is a different story, burned some money there on short time window gains that were marginally relevant), but I did regret saving on it (going with M4 air vs M4 pro)
I recently had some fun overclocking my old i5 4690.
IIRC, running the base frequency at 3.9Ghz instead of 3.5GHz, yield a very modest performance boost but added 20% more power consumption and temperature.
I then underclocked it to 3.1Ghz and the thing barely ran at more than 40°C under load and power consumption was super low! The performance was more than mediocre though...
Devil's Canyon and Haswell-E were great overclockers. I had an i7-4790K re-lidded with liquid metal stable at 4.7GHz all-core and (a bit later) an i7-5960X stable at 4.5GHz all-core. But yes power consumption and thermal output were through the roof.