The redshift-based distance ladder values of the Hubble constant are higher than that inferred by the cosmic microwave background. This discrepancy in the last few years has become highly statistically significant as we have collected more data.
One solution, dubbed early dark energy, posits dark energy making up ~7% of the universe at z~3000 which then turns "suddenly" into radiation. However, could a decay of dark energy during moderate redshifts, i.e. z<10, also reduce or eliminate the Hubble tension? Namely, my dubious logic is if dark energy was stronger in the past, where "past" means z~1-10, it would have given the universe more of a "push" than ΛCDM predicts, accounting for the higher expansion rate today.
We can evolve the Friedman equations with an initial flat-universe condition of T~3000K with the present-day baryon/microwave-photon/other particles ratio but with more dark energy than today (though still negligible until z<~10). I think this gives us enough initial conditions. Each fluid dilutes and contributes density/pressure to the expansion (de)celeration according to its own equation of state. Added to this is a decay of dark energy into radiation or "warm" matter. The rate of decay can be one of many scalar field models, but we are looking at Gyr time-scales. We stop the evolution when our photons hit 2.725K, and measure the Hubble constant.
However, I can't figure out the anisotropies of the CMB play into this picture? So I can't trust my original reasoning.
Edit: I am mainly looking from the perspective of resolving the tension itself rather than the physical plausibility of this occurring. It is possible that the decay is into "dark radiation" which would be hard to detect.