I still don’t see how the Elex can be regarded as bright. Certainly no brighter than the DT1990 (which is known for its bright tilt, though not quite as bright as the painful DT990). Could be something in your system, because while you do get a hint of the metallic nature of the drivers, this is very subtle and hardly present on most well recorded tracks. As someone who’s very treble sensitive, I find the Elex almost perfectly balanced.
I personally don't say 'bright' as the primary characteristic of the Elex, but they have an 'intense' mid to high range -- I chalk this up to less random noise and greater dynamic differences than other drivers. So, at a similar overall listening volume the treble comes across as more defined and impactful and attention-grabbing. The brassy/metallic tone was extremely obvious with female voices and violins at first, as this frequency range was perhaps cleaned up the most with the drivers (my ears might have been accustomed to random noise in this band, or the drivers did have a different tone).
My everyday DAC/Amp is the FiiO Q5 on balanced. The Elex have a mid-high glare to me on single ended, but this declines on balanced.