I’ve got some Grado from the prestige line, and they can be good with the right gear. Perhaps their higher end stuff would be worth a listen. The OP has a fondness for the Sony MDR V6, and I have a pair of the Sony 7605, which is apparently quite close in sound.
But what sounds even better than the Sony’s is the Beyerdynamic DT 770. Detail with very open sound, but not harsh like the Sonys. Made in Germany and not terribly expensive, it’s been in production for around 20 years. In fact, they have recently come out with a new model in the range, and many long time DT770 owners like the improvements.
The DT 770 comes in 3 flavors. 32ohm, 5’ cord. 80 ohm, 10’ cord. 250 ohm, coiled cord. All are hard wired, around $229 each model. All do 5 Hz - 35 kHz. If you prefer open back, the DT 990 is the model. The 80 and 250 ohm versions require a headphone amp.
The DT700 is the new model with different speaker coils. 48 ohm only, detachable cord. Comes with 2 cables - 5.5’ and 9’. $350.
The $700 budget level would need a pretty good headphone amp to take advantage of the SQ available. My Schiit Jotunheim at $400 would probably not be enough for a $700 pair of cans. But the DT 770 are so good at presenting a soundstage, they are the equal of my Hifiman Sundara. The OP might not need to spend more…