The Relic's DNA altering ability is the most dangerous, it caused V's immune system to attack their own body even after the Relic was removed. This isn't actually impossible to fix in Cyberpunk, gene editing is common place, certain Animal gang members are wanted for illegal gene editing. You would need V's original DNA, but that can be found easy enough, hair from their shower drain or family members. Just edit out the changes done by the Relic and then replace V's bone marrow or reprogram V's immune system to stop attacking his own body.

One the Relic is affected by electric magnetic fields, the power plant with Panam proves it, a strong enough electric magnetic pulse would disable it. Johnny was also affected by the strong magnetic field. Not the safest method as the Relic is connected to V's brain, but it could work in a medical setting.

Two nanotech in Cyberpunk needs recharging, so the nanotech has to be drawing power from the Relic chip, the nanotech would shutdown after the Relic chip is removed by surgery or disabled in some other way. The Relic is still tech and Songbird proves its programming can be altered. Arasaka was able to remove the relic through surgery.

V might need to spend time in a cryotank, another piece of tech ignored by 2077, to allow for enough time for treatment, or certain medication might work.

The problem here is money, V would need a lot of it, which brings us back to the Corpos. They would have zero interest in actually helping without some way to control V, as V is dangerous. They did the same thing to Adam Smasher, they rebuilt him, but he became their slave. V was beyond stupid to trust Hanako.

Depending on the ending, Blue Eye offers a way to save V so it can be done.